Filtering method for performing deblocking filtering on a boundary between an intra pulse code modulation block and a non-intra pulse code modulation block which are adjacent to each other in an image

ABSTRACT

A filtering method is for performing deblocking filtering on the boundary between an IPCM block and a non-IPCM block adjacent to each other in an image and including: determining a first quantization parameter for the non-IPCM block; determining a second quantization parameter for the IPCM block, using the first quantization parameter; determining a filter strength for the boundary, using the first quantization parameter and the second quantization parameter; and performing the deblocking filtering on the boundary using the determined filter strength.

TECHNICAL FIELD

One or more exemplary embodiments disclosed herein relate generally to afiltering method, a moving picture decoding method, a moving picturecoding method, a moving picture decoding apparatus, a moving picturecoding apparatus, and a moving picture coding and decoding apparatus.

BACKGROUND ART

Intra Pulse Code Modulation (IPCM) blocks are blocks of uncompressedvideo or image samples where luma and chroma samples are coded in thecoded stream. These blocks are used in the case when the entropy codingunit produces more bits rather than reduces bits when coding the blocksof image samples. In other words, the pixel values of the IPCM blocksare not compressed, ant thus the raw pixel values of the original imageare used. The IPCM block is introduced in the H.264/AVC videocompression standard.

A filtering method in H.264 (the filtering method described in Section8.7 of the H.264 standard) defines that a filter strength for a boundarybetween two blocks is normally determined based on the average value ofa value aPp derived from a quantization parameter QPp of a firstmacroblock and a quantization parameter QPq of a second macroblock. Nodecoding is performed for these blocks. However, post-decodingprocessing (including filtering such as deblocking filtering) is stillperformed on the block boundaries which tend to be a cause ofdeterioration in image quality (for example, see Non-patent Literature(NPL) 1).

CITATION LIST Non Patent Literature

ISO/IEC 14496-10 “MPEG-4 Part 10 Advanced Video Coding”

SUMMARY OF INVENTION Technical Problem

There are demands for performing more appropriate filtering on theboundary between such an IPCM block and a non-IPCM block.

One non-limiting and exemplary embodiment provides a filtering methodfor enabling more appropriate filtering on the boundary between such anIPCM block and a non-IPCM block.

Solution to Problem

A filtering method according to one non-limiting and exemplaryembodiment is a filtering method of performing deblocking filtering on aboundary between an Intra Pulse Code Modulation (IPCM) block and anon-IPCM block which are adjacent to each other in an image, and thisfiltering method includes: determining a first quantization parameterfor the non-IPCM block; determining a second quantization parameter forthe IPCM block and for determining a filter strength, using the firstquantization parameter; determining the filter strength, using the firstquantization parameter and the second quantization parameter; andperforming the deblocking filtering on the boundary, using thedetermined filter strength.

These general and specific aspects may be implemented using a system, amethod, an integrated circuit, a computer program, or acomputer-readable recording medium such as a CD-ROM, or any combinationof systems, methods, integrated circuits, computer programs, orcomputer-readable recording media.

Additional benefits and advantages of the disclosed embodiments will beapparent from the Specification and Drawings. The benefits and/oradvantages may be individually obtained by the various embodiments andfeatures of the Specification and Drawings, which need not all beprovided in order to obtain one or more of such benefits and/oradvantages.

Advantageous Effects of Invention

One exemplary embodiment or feature disclosed herein is a filteringmethod for enabling more appropriate filtering on the boundary betweenan IPCM block and a non-IPCM block.

BRIEF DESCRIPTION OF DRAWINGS

These and other advantages and features will become apparent from thefollowing description thereof taken in conjunction with the accompanyingDrawings, by way of non-limiting examples of embodiments of the presentdisclosure. In the Drawings:

FIG. 1 is a flowchart illustrating a concept of filtering at a blockboundary described in Section 8.7 “Deblocking filter process” in theH.264 Standard;

FIG. 2 is a flowchart illustrating a concept of filtering at a blockboundary described in Section 8.7 “Deblocking filter process” in theH.264 Standard;

FIG. 3 is a flowchart illustrating a concept of filtering at a blockboundary described in Section 8.7 “Deblocking filter process” in theH.264 Standard;

FIG. 4 is an illustration of a filter strength in a filtering methodaccording to Embodiment 1;

FIG. 5 is a flowchart of a filtering method according to Embodiment 1;

FIG. 6 is a block diagram of a moving picture coding apparatus accordingto Embodiment 1;

FIG. 7A is an illustration of an example of a block boundary accordingto Embodiment 1;

FIG. 7B is an illustration of an example of a block boundary accordingto Embodiment 1;

FIG. 8A is an illustration of operations performed by a filtering unitaccording to Embodiment 1;

FIG. 8B is an illustration of operations performed by a filtering unitaccording to Embodiment 1;

FIG. 9 is a block diagram of an image decoding apparatus according toEmbodiment 1;

FIG. 10A is an illustration of an exemplary structure of filtering unitsaccording to Embodiment 1;

FIG. 10B is an illustration of an exemplary structure of a filteringunit according to Embodiment 1;

FIG. 10C is an illustration of an exemplary structure of filtering unitsaccording to Embodiment 1;

FIG. 10D is an illustration of an exemplary structure of a filteringunit according to Embodiment 1;

FIG. 10E is an illustration of an exemplary structure of filtering unitsaccording to Embodiment 1;

FIG. 10F is an illustration of an exemplary structure of filtering unitsaccording to Embodiment 1;

FIG. 10G is an illustration of an exemplary structure of filtering unitsaccording to Embodiment 1;

FIG. 10H is an illustration of an exemplary structure of a filteringunit according to Embodiment 1;

FIG. 11 is a flowchart of a filtering method according to Embodiment 1;

FIG. 12 is a flowchart of a filtering method according to Embodiment 1;

FIG. 13 is an illustration of filter strengths and block units accordingto Embodiment 1;

FIG. 14A is an illustration of an application range of a flag when afilter is ON according to a comparison example;

FIG. 14B is an illustration of an application range of a flag when afilter is ON according to Embodiment 1;

FIG. 15 is a flowchart of a moving picture coding method according to avariation of Embodiment 1;

FIG. 16 is a flowchart of a moving picture decoding method according toa variation of Embodiment 1;

FIG. 17 is a block diagram of a moving picture coding apparatusaccording to Embodiment 2;

FIG. 18 is a block diagram of an image decoding apparatus according toEmbodiment 2;

FIG. 19 is a flowchart of a filtering method according to Embodiment 2;

FIG. 20 is a flowchart of specific examples of a filtering methodaccording to Embodiment 2;

FIG. 21 is a flowchart of a moving picture coding method according to avariation of Embodiment 2;

FIG. 22 is a flowchart of a moving picture decoding method according toa variation of Embodiment 2;

FIG. 23 shows an overall configuration of a content providing system forimplementing content distribution services;

FIG. 24 shows an overall configuration of a digital broadcasting system;

FIG. 25 shows a block diagram illustrating an example of a configurationof a television;

FIG. 26 shows a block diagram illustrating an example of a configurationof an information reproducing/recording unit that reads and writesinformation from and on a recording medium that is an optical disk;

FIG. 27 shows an example of a configuration of a recording medium thatis an optical disk;

FIG. 28A shows an example of a cellular phone;

FIG. 28B is a block diagram showing an example of a configuration of acellular phone;

FIG. 29 illustrates a structure of multiplexed data;

FIG. 30 schematically shows how each stream is multiplexed inmultiplexed data;

FIG. 31 shows how a video stream is stored in a stream of PES packets inmore detail;

FIG. 32 shows a structure of TS packets and source packets in themultiplexed data;

FIG. 33 shows a data structure of a PMT;

FIG. 34 shows an internal structure of multiplexed data information;

FIG. 35 shows an internal structure of stream attribute information;

FIG. 36 shows steps for identifying video data;

FIG. 37 shows an example of a configuration of an integrated circuit forimplementing the moving picture coding method and the moving picturedecoding method according to each of embodiments;

FIG. 38 shows a configuration for switching between driving frequencies;

FIG. 39 shows steps for identifying video data and switching betweendriving frequencies;

FIG. 40 shows an example of a look-up table in which video datastandards are associated with driving frequencies;

FIG. 41A is a diagram showing an example of a configuration for sharinga module of a signal processing unit; and

FIG. 41B is a diagram showing another example of a configuration forsharing a module of the signal processing unit.

DESCRIPTION OF EMBODIMENTS

(Underlying Knowledge Forming Basis of the Present Disclosure)

The inventors have found the problem indicated below.

Before giving descriptions of the exemplarly embodiments, a descriptionis given of inter-pixel filtering (deblocking filtering) in a boundarybetween an IPCM block and a non-IPCM block in coding and decoding inH.264.

FIG. 1 is a flowchart illustrating a concept of filtering at a blockboundary described in Section 8.7 “Deblocking filter process” in theH.264 Standard.

FIG. 1 schematically shows the boundary between the two macroblocks oneof which is the non-IPCM macroblock (the left side in the illustration)and the other is the IPCM macroblock (the right side in theillustration). Three circles positioned at the left side in FIG. 1 showthree pixels (typically, denoted as p0, p1, and p2 sequentially from theboundary). These left-side three pixels belong to a first block (pblock) in a first unit (a coded unit block, hereinafter referred to as aCU block). These three pixels also belong to a first macroblock of anon-IPCM type in a macroblock unit block (hereinafter referred to as anMB) that is a unit larger than the first unit.

Likewise, three circles positioned at the right side in FIG. 1 showthree pixels (typically, denoted as q0, q1, and q2 sequentially from theboundary). These three pixels belong to a second block (a q block) inthe first unit. These three pixels also belong to a second macroblock ofan IPCM type in an MB.

Hereinafter, a CU block that belongs to a macroblock of an IPCM type isreferred to as an IPCM block, and a CU block that belongs to amacroblock of a non-IPCM block is referred to as a non-IPCM block. Inother words, a non-IPCM block means a bock that is not an IPCM block.

Hereinafter, a description is given of a method of determining a filterstrength that is applied to pixels q0, q1, p0, and p1 across the blockboundary (or a boundary between block units larger than the unit ofcoding).

A filtering method in H.264 (the filtering method described in Section8.7 of the H.264 standard) defines that a filter strength for a boundarybetween two blocks is normally determined based on the average value ofa value aPp derived from a quantization parameter QPp of a firstmacroblock and a quantization parameter QPq of a second macroblock.QPav=(QPp+QPq+1)>>1=>(QPp+1)>>1  (Expression 1)

This (Expression 1) shows the following calculation. Filter strengthsare designed such that a stronger (in smoothness) filter is applied asthe value of a quantization parameter is larger, with an aim to, forexample, absorb a quantization error.

In the illustration, a left-side quantization parameter QPp is aquantization parameter that is coded for the first macroblock (p-sideblock). For convenience, QP used here is equivalent in meaning to avalue qP that is used for the purpose of filtering. In addition, aright-side quantization parameter QPq is a quantization parameter thatshould be applied to the second macroblock (q-side block).

Here, as described in Section 8.7.2 of the H.264 Standard, the value ofthe quantization parameter qPq (QPq in the illustration) of the IPCMblock is set to 0. In other words, “Both sides filtered with weakstrength” is realized. This means that, as for a boundary between twoblocks, a filter having a filter strength is applied to both the blocks.This also means that it is impossible to differentiate filter strengthsfor the respective two blocks. In other words, filtering using the samefilter strength is executed on both the blocks across the boundarybetween an IPCM block and a non-IPCM block.

FIG. 2 is a flowchart illustrating a concept of filtering at a blockboundary described in Section 8.7 “Deblocking filter process” in theH.264 Standard.

This flowchart roughly explains the following three points regarding anH.264 filter.

(1) Order of Determining Filter Strength (bS) in Clause 8.7.2.1

Step S101 corresponds to the process of “Deviation process for the lumacontent dependent boundary filtering strength” described in Section8.7.2.1. This process determines a filter strength in filtering on ablock boundary according to a block type and the like. Here, the filterstrength is classified into a level among levels ranging from strongfiltering (bS=4) to no filtering (bS=0). This point is described withreference to FIG. 3.

(2) Process of Setting Quantization Parameter qPz=0 for IPCM Block

Steps S102 to S107 are processes for setting a value of a quantizationparameter qP for determining a filter strength as described withreference to FIG. 1. As for normal non-IPCM blocks (No in Step S102 orS105), the quantization parameter QP [i] (i denotes 0 or 1) of amacroblock to which the non-IPCM block belongs is set as a quantizationparameter qP [i] for determining a filter strength (Step S103 and S106).On the other hand, when a current block is an IPCM block (Yes in S102 orS105), the quantization parameter qP of the IPCM block is set to 0 (StepS104 and S107).

Next, in Step S108, qPav is calculated according to (Expression 1).

(3) One bS (or filterSampleFlag) is Shared by Both Blocks

Hereinafter, a description is given of applying a determined filterstrength (a value) (or a determination flag specifying whether toperform filtering or not) in common to two blocks across a boundary.

First, after Step S108, calculation using Expressions from 8-462 to8-467 in the Standard is performed. More specifically, (1) derivation ofan index for slight adjustment of a filter strength that is set in StepS101 and (2) derivation of a threshold value for edge determination areperformed.

Then, the filter strength determined through these processes is set toboth the blocks (S109). More specifically, even when the filter strengthbS is any one of 1 to 4, the value derived using the common bS derivingmethod is applied to the two blocks. For example, when the filterstrength bS=4 is satisfied, the value of the pixel p of the first blockis derived using Expressions (8-486 and 8-487) in the Standard. Inaddition, the value of the pixel q included in the second block isderived using the same filter strength as the filter strength used inthe derivation of the value of the pixel p. Furthermore, a determinationon whether to perform filtering (derivation of the value offilterSamplesFlag (also referred to as a filtering execution flag)) isperformed in preparation for, for example, a case where a block boundaryis finally found to be an actual edge. More specifically, thisdetermination is made by comparison between two threshold values(two_threths (α, β)) derived in Step S109 and actual pixel values of pand q (see Expression (8-468) in the Standard). However, as describedabove, it is impossible to set different values (or execution ornon-execution) as the filter strengths bS or the filtering executionflags for the respective two blocks.

In other words, in H.264, it is impossible to perform processingsuitable for IPCM when seen within a filtering process.

FIG. 3 is a flowchart indicating the order of deciding (order ofdetermining) a filter strength (bS) that is applied to pixels locatedacross a boundary between two macroblocks, as described in Clause8.7.2.1 of the Standard. This flowchart illustrates the determinationorder in Step S101 shown in FIG. 2, and conforms to the determinationflow in Clause 8.7.2.1 of the Standard.

First, a determination is made as to whether the boundary defined by thepixel p0 in the first block and the pixel q0 in the second block alsocorresponds to a boundary between macroblocks or not (S121). In otherwords, a determination is made as to whether p0 and q0 are locatedacross the macroblock boundary.

When the block boundary between the processing targets is not amacroblock boundary (No in S121), the filter strength (bS) is determinedto be any one of 3, 2, 1, and 0 that is smaller than N(=4) (S124).

On the other hand, when the block boundary between the processingtargets is a macroblock boundary (Yes in S121), a determination is madeas to whether one (or both) of p0 and q0 belongs to a macroblock codedusing the intra prediction mode (S122).

When both the blocks do not belong to a macroblock coded using the intraprediction mode (No in S122), a determination based on anotherdetermination factor is executed (S125).

On the other hand, when at least one of the blocks belongs to amacroblock coded using the intra prediction mode (Yes in S122), thefilter strength is (always) set to bS=4 that means the highest strengthwithout considering any other determination factor (S123).

In this way, the conventional filtering method does not make it possibleto execute internal filtering processes for such two blocks that arelocated across the boundary in different manners (in terms of filterstrengths and application or non-application of a filter). In addition,the Standard considers processes up to the determination of a filterstrength focusing on IPCM, but does not make it possible to performcontrol for outputting raw pixel values of an IPCM block when one of theblocks is an IPCM block and the other is a non-IPCM block.

An IPCM block is a block including pixel values faithfully showing “theoriginal image” without a coding loss. Accordingly, in the filteringprocess, it is possible to control filtering at the boundary with anIPCM block or to control application of a filter to the IPCM block.

In addition, as described above, the filter strength for the boundarybetween two blocks is generally determined based on the value qPpderived from the quantization parameter QPp for the first macroblock andthe value qPav derived from the quantization parameter QPq for thesecond macroblock. Furthermore, the value of the quantization parameterqPq for the IPCM block is set to 0. In this way, the average value qPavfor determining the filter strength for the boundary between the IPCMblock and the non-IPCM block is half the value of the quantizationparameter QPq for the non-IPCM block. In other words, the average valueqPav is inevitably small at the boundary between the IPCM block and thenon-IPCM block, compared to a normal case (of the boundary betweennon-IPCM blocks). In this way, the inventors have found that it isimpossible to set an appropriate filter strength for the boundarybetween such an IPCM block and a non-IPCM block.

In view of this, a filtering method according to one non-limiting andexemplary embodiment is a filtering method of performing deblockingfiltering on a boundary between an Intra Pulse Code Modulation (IPCM)block and a non-IPCM block which are adjacent to each other in an image,and this filtering method includes: determining a first quantizationparameter for the non-IPCM block; determining a second quantizationparameter for the IPCM block and for determining a filter strength,using the first quantization parameter; determining the filter strength,using the first quantization parameter and the second quantizationparameter; and performing the deblocking filtering on the boundary,using the determined filter strength.

In this way, with the filtering method according to one non-limiting andexemplary embodiment, it is possible to determine the quantizationparameter for the IPCM block, using the quantization parameter for thenon-IPCM block. In this way, with the filtering method, it is possibleto perform appropriate filtering on the boundary between the IPCM blockand the non-IPCM block, compared to the case of using zero as thequantization parameter for the IPCM block.

In addition, in the determining of a second quantization parameter, avalue of the second quantization parameter may be set to be same as avalue of the first quantization parameter.

In addition, in the determining of the filter strength, an average valuebetween the first quantization parameter and the second quantizationparameter may be calculated, and the filter strength may be determinedusing the calculated average value.

Furthermore, a moving picture decoding method according to onenon-limiting and exemplary embodiment is a moving picture decodingmethod of decoding a coded bit stream, and this moving picture decodingmethod includes: parsing the coded bit stream and obtain differenceinformation indicating that a difference between a quantizationparameter for a block which is located immediately before a currentblock to be processed in processing order and a quantization parameterfor the current block is zero; and the filtering method, wherein, in thedetermining of a second quantization parameter, a value of the secondquantization parameter is set to be same as a value of the firstquantization parameter according to the difference information.

In this way, with the moving picture decoding method according to onenon-limiting and exemplary embodiment, it is possible to determine thequantization parameter for the IPCM block according to differenceinformation that is used for another purpose. Thus, with the movingpicture decoding method, it is possible to appropriately determine thequantization parameter for the IPCM block without adding, to the movingpicture decoding apparatus, any function for performing specialprocessing on the IPCM block.

In addition, in the determining of a second quantization parameter, whenthe non-IPCM block is located immediately before the IPCM block in theprocessing order, the value of the second quantization parameter may beset to be the same as the value of the first quantization parameteraccording to the difference information.

In addition, the moving picture decoding method may further include:decoding the coded bit stream to generate a quantized coefficient;performing inverse quantization and inverse transform on the quantizedcoefficient to generate a decoded residual signal; and adding aprediction image signal to the decoded residual signal to generate adecoded image signal, wherein the IPCM block and the non-IPCM block maybe included in the decoded image signal, the moving picture decodingmethod may further include performing prediction using an image signalresulting from the deblocking filtering in the filtering method, togenerate the prediction image signal.

In addition, the moving picture decoding method may further includeswitching between decoding that conforms to a first standard anddecoding that conforms to a second standard according to an identifierindicating one of the first standard and the second standard, theidentifier being included in the coded bit stream, wherein when theidentifier indicates the first standard, the parsing and the filteringmethod may be performed as the decoding that conforms to the firststandard.

Furthermore, a moving picture coding method according to onenon-limiting and exemplary embodiment is a moving picture coding methodof coding an input image signal to generate a coded bit stream, and thismoving picture coding method includes: the filtering method; andgenerating the coded bit stream including difference informationindicating that a difference between a quantization parameter for ablock which is located immediately before a current block to beprocessed in processing order and a quantization parameter for thecurrent block is zero, the difference information being generated asinformation indicating that the value of the second quantizationparameter is same as the value of the first quantization parameter.

In this way, with the moving picture coding method according to onenon-limiting and exemplary embodiment, it is possible to transmit, tothe moving picture decoding apparatus, information that allows themoving picture decoding apparatus to determine the quantizationparameter for the IPCM block using the difference information used foranother purpose. Thus, with the moving picture decoding method, themoving picture decoding apparatus can appropriately determine thequantization parameter for the IPCM block without the need that themoving picture decoding apparatus has a function for performing specialprocessing on the IPCM block.

In addition, in the generating, the difference information may begenerated when the non-IPCM block is located immediately before the IPCMblock in the processing order.

In addition, the moving picture coding method may further include:subtracting a prediction image signal from the input image signal togenerate a residual signal; performing transform and quantization on theresidual signal to generate a quantized coefficient; coding thequantized coefficient to generate the coded bit stream; performinginverse quantization and inverse transform on the quantized coefficientto generate a decoded residual signal; and adding the predicted imagesignal to the decoded residual signal to generate a decoded imagesignal, wherein the IPCM block and the non-IPCM block may be included inthe decoded image signal, the moving picture coding method may furtherinclude performing prediction using an image signal resulting from thedeblocking filtering in the filtering method, to generate the predictionimage signal.

Furthermore, a moving picture decoding apparatus according to onenon-limiting and exemplary embodiment is a moving picture decodingapparatus which performs deblocking filtering on a boundary between anIntra Pulse Code Modulation (IPCM) block and a non-IPCM block which areadjacent to each other in an image, and this moving picture decodingapparatus includes: a first quantization parameter determining unitconfigured to determine a first quantization parameter for the non-IPCMblock; a second quantization parameter determining unit configured todetermine a second quantization parameter for the IPCM block and fordetermining a filter strength, using the first quantization parameter; afilter strength determining unit configured to determine the filterstrength, using the first quantization parameter and the secondquantization parameter; and a filter unit configured to performdeblocking filtering on the boundary, using the determined filterstrength.

With this structure, the moving picture decoding apparatus according toone non-limiting and exemplary embodiment determines the quantizationparameter for the IPCM block, using the quantization parameter for thenon-IPCM block. In this way, the moving picture decoding apparatus canperform more appropriate filtering on the boundary between the IPCMblock and the non-IPCM block, compared to the case of using zero as thequantization parameter for the IPCM block.

Furthermore, a moving picture coding apparatus according to onenon-limiting and exemplary embodiment is a moving picture codingapparatus which performs deblocking filtering on a boundary between anIntra Pulse Code Modulation (IPCM) block and a non-IPCM block which areadjacent to each other in an image, and this moving picture codingapparatus includes: a first quantization parameter determining unitconfigured to determine a first quantization parameter for the non-IPCMblock; a second quantization parameter determining unit configured todetermine a second quantization parameter for the IPCM block and fordetermining a filter strength, using the first quantization parameter; afilter strength determining unit configured to determine the filterstrength, using the first quantization parameter and the secondquantization parameter; and a filter unit configured to performdeblocking filtering on the boundary, using the determined filterstrength.

With this structure, the moving picture coding apparatus according toone non-limiting and exemplary embodiment determines the quantizationparameter for the IPCM block, using the quantization parameter for thenon-IPCM block. In this way, the moving picture coding apparatus canperform more appropriate filtering on the boundary between the IPCMblock and the non-IPCM block, compared to the case of using zero as thequantization parameter for the IPCM block.

In addition, the moving picture coding and decoding apparatus accordingto one non-limiting and exemplary embodiment includes the moving picturecoding apparatus and the moving picture decoding apparatus.

These general and specific aspects may be implemented using a system, amethod, an integrated circuit, a computer program, or acomputer-readable recording medium such as a CD-ROM, or any combinationof systems, methods, integrated circuits, computer programs, orcomputer-readable recording media.

Hereinafter, moving picture decoding apparatuses and moving picturecoding apparatuses according to certain exemplary embodiments aredescribed in greater detail with reference to the accompanying Drawings.

Each of the exemplary embodiments described below shows a general orspecific example. The numerical values, shapes, materials, structuralelements, the arrangement and connection of the structural elements,steps, the processing order of the steps etc. shown in the followingexemplary embodiments are mere examples, and therefore do not limit thescope of the appended Claims and their equivalents. Therefore, among thestructural elements in the following exemplary embodiments, structuralelements not recited in any one of the independent claims are describedas arbitrary structural elements.

[Embodiment 1]

Hereinafter, a description is given of a filtering method according toEmbodiment 1.

FIG. 4 illustrates a concept of a method of determining a factor forapplication of the filtering method according to this embodiment anddetermining a filter strength of an inter-pixel filter. Three circles inthe illustration show pixels included in the first block as in FIG. 1.The same elements as in FIG. 1 among the remaining elements are notdescribed again.

A filtering method according to this embodiment is for filtering aplurality of blocks included in an image. Typically, the filteringmethod is applied to deblocking filtering that is performed on aboundary between adjacent blocks. Hereinafter, a description is given ofan example of applying deblocking filtering to the exemplaryembodiments. However, the exemplary embodiments are also applicable toin-loop filtering (Adaptive Loop Filter) other than deblockingfiltering.

The filtering method according to this embodiment is different from thefiltering method described with reference to FIG. 1 in the pointsindicated below.

First, unfiltered pixel values are output as the pixel values of threepixels of the block that is IPCM at the right side in the illustration.

In addition, control is performed to differentiate filtering for thefirst block and filtering for the second block. For example, a filter isapplied to one (at the left side) of the blocks across the boundary inthe illustration, and no filter is applied to the other (at the rightside). In this way, such control for performing the different filteringprocesses between the blocks is performed.

Next, the filter strength for the left-side block to which the filter isapplied is derived based only on the quantization parameter QPp of theleft-side block. In other words, the filter strength of the non-IPCMblock at the left side is derived without using the quantizationparameter QPq of the right-side macroblock or any other substitute fixedvalue (0 in the conventional example).

A determination regarding IPCM in H.264 shown in FIG. 2 is made as towhether the IPCM is an IPCM macroblock or not. Here, such adetermination is made as to whether the IPCM is a prediction unit (PU)that has a variable size. In other words, an IPCM block below is a blockthat belongs to a PU block of an IPCM type, and a non-IPCM block is ablock that belongs to a PU block of a non-IPCM type.

Hereinafter, these operations are described with reference to thedrawings.

FIG. 5 is a flowchart of a processing order in a filtering methodaccording to this embodiment.

The filtering method according to this embodiment is executed as a partof coding processes or decoding processes. Accordingly, this filteringmethod is executed by one of a filtering unit in a coding loop within amoving picture coding apparatus shown in FIG. 6 described later and afiltering unit in a decoding loop within a moving picture decodingapparatus shown in FIG. 9 described later, and a control unit forcontrolling the filter.

The control unit determines whether the PU block type of one of the twoblocks sharing the boundary is IPCM or not (S201). In the exemplary caseof FIG. 4, the right-side PU block is an IPCM block, and thus the one isdetermined to be of an IPCM type. More specifically, the control unitexecutes this determination using a macroblock type, or an attributeparameter of image data such as a motion compensation block size.

When at least one of the two blocks is an IPCM block (Yes in S201), thecontrol unit determines whether the other of the two blocks is an IPCMblock or not (S202). For example, as in the case of the illustration inFIG. 4, the right-side block is an IPCM block. Accordingly, the controlunit determines whether the other block that is the left-side block isan IPCM block or not.

In other words, in steps S201 and S202, the control unit determineswhether each of the blocks is an IPCM block or a non-IPCM block. Morespecifically, the control unit determines (1) whether both of the twoblocks are non-IPCM blocks (No in S201), and (2) whether both of the twoblocks are IPCM blocks (Yes in S202) or (3) whether one of the blocks isan IPCM block and the other is a non-IPCM block (No in S202).

When the other block is an IPCM block (Yes in S202), that is, when boththe blocks are IPCM blocks, filtering is skipped for the pixels p and qof both the blocks (both of the first block and the second block (S203).

On the other hand, when the other block is not an IPCM block (No inS202), that is, only one of the blocks is an IPCM block, and the otheris a non-IPCM block, the control unit performs control for causing thefiltering unit to execute filtering in Steps S204 and S205.

First, the filtering unit executes filtering using a predeterminedstrength on pixels included in the non-IPCM block (for example, thethree pixels at the left side in FIG. 4), and outputs the filtered pixelvalues as the pixel values of the non-IPCM block (S204). In addition,this filtering also uses pixel values of an IPCM block, in addition tothe pixel values of the non-IPCM block. More specifically, the filteringunit smoothes the pixel values of the non-IPCM block and the pixelvalues of the IPCM block to calculate the pixel values of the filterednon-IPCM block.

In addition, the filtering unit outputs the unfiltered pixel values forthe pixels included in the IPCM block (pixels q0, q1, . . . at the qside) (S205). Here, the unfiltered pixel values are output in thefollowing two conceivable cases.

A first method is a method of filtering a non-IPCM block, and outputtingthe original pixel values of an IPCM block without filtering.

A second method is a method of filtering both of a non-IPCM block and anIPCM block, replacing the pixel values of the IPCM block among thefiltered pixel values by the original pixel values before the filtering,and outputting the replacement pixel values. In any one of the cases,the IPCM block's pixel values that are output are the original pixelvalues before the execution of the filtering.

The filtering method can be regarded as involving control for takingdifferent filtering approaches (filter strengths, application ornon-application of a filter, and the number(s) of pixels in theapplication) between the blocks.

The filtering (especially, operations by the control unit and thefiltering unit) in Steps S204 and S205 are described later withreference to FIGS. 6 to 8.

In addition, when both the blocks are non-IPCM blocks in Step S201 (Noin S201), the control unit performs default filtering operation (S206).In other words, the control unit executes filtering using apredetermined filter strength on both the blocks.

Hereinafter, a description is given of a moving picture coding apparatuswhich performs the filtering method.

FIG. 6 is a functional block diagram of a moving picture codingapparatus 100 according to this embodiment. The moving picture codingapparatus 100 shown in FIG. 6 codes an input image signal 120 togenerate a coded bit stream 132. The moving picture coding apparatus 100comprises a subtractor 101, an orthogonal transform unit 102, aquantization unit 103, an inverse quantization unit 104, an inverseorthogonal transform unit 105, an adder 106, a filtering unit 115, amemory 109, a prediction unit 110, a variable length coding unit 111, aselecting unit 112, and a control unit 113.

The subtractor 101 calculates a difference between the input imagesignal 120 and a prediction image signal 130 to generate a residualsignal 121. The orthogonal transform unit 102 performs orthogonaltransform on the residual signal 121 to generate a transform coefficient122. The quantization unit 103 quantizes the transform coefficient 122to generate the quantized coefficient 123.

The inverse quantization unit 104 performs inverse quantization on thetransform coefficient 123 to generate the transform coefficient 124. Theinverse orthogonal transform unit 105 performs inverse orthogonaltransform on the transform coefficient 124 to generate a decodedresidual signal 125. The adder 106 adds the decoded residual signal 125and the prediction image signal 130 to generate a decoded image signal126.

The filtering unit 115 filters the decoded image signal 126 to generatean image signal 128, and stores the generated image signal 128 in thememory 109.

The prediction unit 110 selectively performs intra prediction and interprediction using the image signal 128 stored in the memory 109 togenerate a prediction image signal 130.

The variable length coding unit 111 performs variable length coding(entropy coding) on the quantized coefficient 123 to generate a codedsignal 131.

The selecting unit 112 selects the input image signal 120 when a currentblock is an IPCM block, and selects a coded signal 131 when a currentblock is a non-IPCM block. Then, the selecting unit 112 outputs theselected signal as a coded bit stream 132.

The control unit 113 controls the filtering unit 115 and the selectingunit 112.

Here, the orthogonal transform unit 102 and the quantization unit 103are examples of transform and quantization units which generate aquantization coefficient by performing transform and quantization on theresidual signal. In addition, the variable length coding unit 111 is anexample of a coding unit which codes the quantized coefficient togenerate a coded signal. In other words, the inverse quantization unit104 and the inverse orthogonal transform unit 105 are examples of aninverse quantization unit and an inverse transform unit which generate adecoded residual signal by performing inverse quantization and inversetransform on the quantized coefficient.

Here, especially major elements of the moving picture coding apparatus100 according to this embodiment are the control unit 113 and thefiltering unit 115.

As described above, the filtering method according to this embodiment isexecuted as parts of the coding processes and the decoding processes.Accordingly, the filtering unit 115 is located before the memory 109 forholding reference pictures etc. The filtering unit 115 stores, in thememory 109 in the loops, the result of executing the filtering (or theresult of skipping the filtering). In this respect, the filtering unit115 is the same as a filter called a Loop filter in H.264. In addition,the filtering unit 115 has two input lines. A first one of the inputsignals is a decoded image signal 126 representing the pixel values ofthe non-IPCM block, and a second one of the input signals is an inputimage signal 120 representing the pixel values of the IPCM block. Here,the decoded image signal 126 is a reconstructed coded image signal afterbeing subjected to transform, quantization, inverse quantization, andinverse transform. In addition, the input image signal 120 is theoriginal image signal which is not subjected to the coding and decoding.

Under control of the control unit 113, the filtering unit 115 outputsthe unfiltered original pixel values of the IPCM block, and filters thepixel values of the non-IPCM block and outputs the filtered values.

This filtering unit 115 includes a filter unit 107 and a selecting unit108. The filter unit 107 filters the decoded image signal 126 togenerate an image signal 127. The selecting unit 108 selects the imagesignal 127 when a current block is an IPCM block, and selects an inputimage signal 120 when a current block is a non-IPCM block and thenoutputs the selected signal as an image signal 128.

Each of FIGS. 7A and 7B is an illustration of an example of pixelsacross a boundary between two blocks. In the example shown in FIG. 7A,the two blocks are adjacent to each other in the horizontal direction.Here, the block including the pixels p0 to pn at the left side isreferred to as a first block. This first block is a non-IPCM block. Inaddition, the other block is referred to as a second block. This secondblock is an IPCM block. Here, as shown in FIG. 7B, the filtering in thisembodiment is naturally applicable in the case where an IPCM block and anon-IPCM block are adjacent to each other in the vertical direction.

Hereinafter, a description is given of a specific example of operationsby the filtering unit 115.

Each of FIG. 8A and FIG. 8B is an illustration of operations performedby the filtering unit 115 in the case of filtering pixels p [i] and q[j] included in the two blocks illustrated in FIG. 7A. In other words,the first block belongs to the non-IPCM block, and the second block isthe IPCM block.

The filtering unit 115 performs operations shown in FIG. 8A and FIG. 8Baccording to a control signal from the control unit 113.

FIG. 8A is an illustration of an operation by the filtering unit 115 onthe non-IPCM block. This operation corresponds to Step S204 shown inFIG. 5. In other words, the filtering unit 115 calculates output resultspf0, pf1, . . . of the pixels corresponding to the first block, usingboth the pixel values (p0, p1, . . . ) of the first block and the pixelvalues (q0, q1, . . . ) of the second block.

FIG. 8B is an illustration of operations by the filtering unit 115 onthe IPCM block. This operation corresponds to Step S205 shown in FIG. 5.In other words, the filtering unit 115 outputs the same values(unfiltered pixel values) as the input values q0, q1, and q2, for thepixels of the second block.

Hereinafter, a description is given of a moving picture decodingapparatus which performs the filtering method.

FIG. 9 is a functional block diagram of a moving picture decodingapparatus according to this embodiment.

The moving picture decoding apparatus 200 shown in FIG. 9 decodes thecoded bit stream 232 to generate an output image signal 220. Here, thecoded bit stream 232 is, for example, a coded bit stream 132 generatedby the moving picture coding apparatus 100.

This moving picture decoding apparatus 200 comprises an inversequantization unit 204, an inverse orthogonal transform unit 205, anadder 206, a filtering unit 215, a memory 209, a prediction unit 210, avariable length decoding unit 211, a distributing unit 212, and acontrol unit 231.

The distributing unit 212 supplies the coded bit stream 232 to thefiltering unit 215 when a current block is an IPCM block, and suppliesthe coded bit stream 232 to the variable length decoding unit 211 when acurrent block is a non-IPCM block.

The variable length decoding unit 211 performs variable length decoding(entropy decoding) on the coded bit stream 232 to generate a quantizedcoefficient 223.

The inverse quantization unit 204 performs inverse quantization on thetransform coefficient 223 to generate the transform coefficient 224. Theinverse orthogonal transform unit 205 performs inverse orthogonaltransform on the transform coefficient 224 to generate a decodedresidual signal 225. The adder 206 adds the decoded residual signal 225and the prediction image signal 230 to generate a decoded image signal226.

The filtering unit 215 filters the decoded image signal 226 to generatean image signal 228, and stores the generated image signal 228 in thememory 209.

This filtering unit 215 includes a filter unit 207 and a selecting unit208. The filter unit 207 filters the decoded image signal 226 togenerate an image signal 227. The selecting unit 208 selects the imagesignal 227 when a current block is an IPCM block, and selects an inputimage signal 232 when a current block is a non-IPCM block and thenoutputs the selected signal as an image signal 228.

In addition, the image signal 228 stored in the memory 209 is output asan output image signal 220.

The prediction unit 210 selectively performs intra prediction and interprediction using the image signal 228 stored in the memory 209 togenerate a prediction image signal 230.

The control unit 213 controls the filtering unit 215 and thedistributing unit 212.

Here, the variable length decoding unit 211 is an example of a decodingunit which decodes the coded bit stream to generate a quantizedcoefficient.

Here, operations by the filtering unit 215 are the same as operations bythe filtering unit 115 of the moving picture coding apparatus 100. Thecontrol unit 213 is different from the control unit 113 included in themoving picture coding apparatus 100 in the point of determining whetherthe PU unit type of the first block or the second block is IPCM or notfrom the coded bit stream 232 that is an input coded string, but is thesame in the other functions.

Hereinafter, descriptions are given of structures of variations of thefiltering units 115 and 215.

Each of FIG. 10A to FIG. 10H is an illustration of a conceivableimplementation regarding a filter input-output relationship of filteringunits 115 and 215.

As shown in FIG. 10A, each of the filter units 107 and 207 may includefilter units 301 and 302 connected in series. For example, the firstfilter unit 301 and the second filter unit 302 may perform differentprocesses. In this case, for example, the whole filtering processes arebypassed for the IPCM block.

As shown in FIG. 10B, the filter unit 311 may perform filtering usingboth the input signals. In this case, the selecting unit 312 outputsunfiltered values for the IPCM block, and the filter unit 311 outputsfiltered values for the non-IPCM block.

As shown in FIG. 10C, it is also good to perform filtering processesdifferent between the IPCM block and the non-IPCM block. For example,different filtering processes may be filtering processes using differentfilter strengths. In addition, for example, the filter strength for theIPCM block may be lower than the filter strength for the non-IPCM block.

More specifically, the distributing unit 321 outputs the input signal tothe filter unit 322 when a current block is a non-IPCM block, andoutputs the input signal to the filter unit 323 when a current block isan IPCM block. Here, the input signals include both the decoded imagesignal 126 and the input image signal 120. The filter unit 322 performsfiltering of a first filter strength using the input signal to generatepixel values of the current block. The filter unit 322 performsfiltering using a second filter strength lower than the first filterstrength to generate pixel values of the current block. The selectingunit 324 outputs the pixel values of the current block filtered by thefilter unit 322 when the current block is the non-IPCM block, andoutputs the pixel values of the current block filtered by the filterunit 323 when the current block is the IPCM block.

As shown in FIG. 10D, processing on the IPCM block does not always needto be performed. More specifically, the distributing unit 331 outputsthe input signal to the filter unit 332 when a current block is anon-IPCM block, and outputs the input signal to the selecting unit 333when a current block is an IPCM block. The selecting unit 333 outputsthe pixel values of the current block filtered by the filter unit 332when the current block is the non-IPCM block, and outputs the pixelvalues of the current block in the signal from the filter unit 331 whenthe current block is the IPCM block.

As shown in FIG. 10E, it is possible to switch input sides of filterunits instead of switching output sides of the filter units.Furthermore, the numbers of the stages of filter units are differentbetween an IPCM block and a non-IPCM block. More specifically, thedistributing unit 341 outputs the input signal to the filter unit 342when a current block is a non-IPCM block, and outputs the input signalto the filter unit 344 when a current block is an IPCM block. The filterunit 342 performs filtering using the input signal. The filter unit 343performs filtering using the signal filtered by the filter unit 342, andoutputs the pixel values of the current filtered block. The filter unit344 performs filtering using the input signal, and outputs the pixelvalues of the current filtered block. Here, the filtering performed bythe filter unit 344 may be the same as or different from the filteringperformed by the filter unit 342 and the filtering performed by thefilter unit 343.

As shown in FIG. 10F, it is possible to switch output sides of filterunits. More specifically, the filter unit 351 performs filtering usingthe first input signal. The filter unit 352 performs filtering using thesignal filtered by the filter unit 351, and outputs the pixel values ofthe current filtered block. The filter unit 353 performs filtering usingthe second input signal, and outputs the pixel values of the currentfiltered block. The selecting unit 354 outputs the pixel values of thecurrent block filtered by the filter unit 352 when the current block isthe non-IPCM block, and outputs the pixel values of the current blockfiltered by the filter unit 353 when the current block is the IPCMblock.

Here, outputting an unfiltered value involves replacing a pixel valueresulting from filtering by the original input value p and outputtingthe replacement value.

As shown in FIG. 10G, it is possible to use a signal filtered in one oftwo lines in filtering that is performed in the other line. Morespecifically, the filter unit 361 performs filtering using the secondinput signal. The filter unit 352 performs filtering using the firstinput signal and a signal filtered by the filter unit 361. The selectingunit 363 outputs the pixel values of the current block filtered by thefilter unit 362 when the current block is the non-IPCM block, andoutputs the pixel values of the current block filtered by the filterunit 361 when the current block is the IPCM block. The selecting unit363 may output the pixel values of the current block filtered by thefilter unit 362 when the current block is the IPCM block, and output thepixel values of the current block filtered by the filter unit 361 whenthe current block is the non-IPCM block.

As shown in FIG. 10H, a value stored once in the memory 373 may be usedas an input. More specifically, the selecting unit 371 selects one ofthe input signal and the signal stored in the memory 373. The filterunit 372 performs filtering using the signal selected by the selectingunit 371.

These are examples, and thus it is only necessary for the filtering unit115 according to this embodiment to exert a function of finally“outputting unfiltered values for the pixels in an IPCM block”.

Hereinafter, a description is given of a modified version of a filteringmethod according to this embodiment. FIG. 11 is a flowchart ofoperations in the modified version of the filtering method according tothis embodiment.

It has been described that filtering is applied to the non-IPCM block inStep S204 of FIG. 5 and unfiltered pixel values of the IPCM block areoutput in Step S205 of FIG. 5. However, these processes may be realizedin the steps indicated below. For example, it is possible to performprocesses shown in FIG. 11 instead of Steps S204 and S205 shown in FIG.5.

First, pixel values of a first block (block [0]) and a second block(block y [1]) adjacent to each other are obtained (S221). Here, forexample, the first block is a non-IPCM block, and the second block is anIPCM block.

Next, a filter strength bS [0] that is applied to the first block and afilter strength bS [1] that is applied to the second block are derived(S222 and S223). Here, the filter strength bS [0] and the filterstrength bS [1] show different strengths. In the conventional art, onlyone filter strength is set for a block boundary. For example, in thisembodiment, the filter strength for the IPCM block is set lower than thefilter strength for the non-IPCM block.

Next, both the blocks are filtered using the filter strength bS [0], andthe pixel values of the second block after the filtering are output(S125). Next, both the blocks are filtered using the filter strength bS[1], and the pixel values of the second block after the filtering areoutput (S225).

Here, it is possible to control application or non-application offiltering by setting the value of the filter strength to 0. In otherwords, it is also good to derive for each of the blocks a flag(filterSamplesFlag) for controlling application or non-application offiltering.

As described above, the filtering method according to this embodimentmakes it possible to execute filtering on one of the blocks using thefirst filter strength and execute filtering on the other block using thesecond filter strength. In addition, the filtering method makes itpossible to perform such processing in filtering processes.

FIG. 12 is a flowchart of operations in a variation of the filteringmethod according to this embodiment. The processes shown in FIG. 12further include Step S401, in addition to the processes shown in FIG. 3.

This Step S401 is added to provide an appropriate filter strength to anIPCM block which is inevitably determined to be a block that is intrapredicted. In Step S401, a determination is made as to whether at leastone of the first block and the second block is an IPCM block or not.When at least one of the first block and the second block is the IPCMblock (Yes in S401), a filter strength (bS) is determined to be any oneof 3, 2, 1, and 0 that is smaller than N (=4) (S124). In addition, whenboth the first block and the second block are non-IPCM blocks (No inS401), the filter strength is set to bS=N which means the higheststrength (S123).

In the case of the filtering method shown in FIG. 3, when one or both ofthe blocks is a macroblock coded using the intra prediction mode (Yes inS122), the filter strength itself is always set to be bS=4 which meansthe highest strength without considering any other determination factor.

On the other hand, in the case of this embodiment's variation shown inFIG. 12, when one or both of the blocks is a macroblock coded using theintra prediction mode (Yes in S122) and when one of the blocks is anIPCM block (Yes in S401), a filter strength (bS=0 to 3) lower than thefilter strength (bS=4) set in Step S123 is set.

FIG. 13 is an illustration of filter strengths determined using thefiltering method according to this embodiment and block units whichdefine a boundary.

As shown in FIG. 13, when a macroblock MB [0] is a macroblock codedusing the inter prediction mode and a macroblock MB [1] is a macroblockcoded using the intra prediction mode (Yes in S122) and when both thefirst and second blocks are non-IPCM blocks (No in S401), bS=4 is set toboth the blocks (S123).

On the other hand, when a PU block [0] is coded using a non-IPCM modeand a PU block [1] is coded using an IPCM mode, that is, when a CU block[0] is a non-IPCM block and a CU block [1] is an IPCM block (Yes inS401), bS=any one of 0 to 3 is set to each of the CU block [0] and CUblock [1]. In this example, bS=0 is set to the CU block [1] that is anIPCM block, and bS=any one of 1 to 3 is set to the CU block [0] that isa non-IPCM block.

Each of FIG. 14A and FIG. 14B is an illustration of a state in which anapplication range of a flag indicating that a filter is ON is extendedby handling an IPCM block according to this embodiment. FIG. 14A shows,as a comparison example, a case of not applying an approach in thisembodiment. FIG. 14B shows a case of applying the approach in thisembodiment.

As shown in FIG. 14B, it is possible to extend the application range ofthe flag indicating that a filter is ON by using the filtering methodaccording to this embodiment.

As described above, the filtering method according to this embodimentemploys, for the determination, an implicit code interpretation rulethat the filtering unit or the control unit “does not filter an IPCMblock” in the in-loop filtering. In this way, as shown in FIG. 14A andFIG. 14B, it is possible to specify whether a filter is enabled ordisabled for a coded string in a larger range. In this way, thefiltering method according to this embodiment reduces the amount ofbits.

Although examples of applying this embodiment to deblocking filteringhave been described in the above descriptions, but similar methods areapplicable to other processing. For example, it is possible to apply theprocessing to adaptive loop filtering (ALF) or adaptive offset, insteadof the deblocking filtering.

The deblocking filtering is filtering that is used for a reconstructedpixel sample that is located near a block boundary. Deblocking filteringreduces noise that is generated at the block boundary due toquantization that is performed on a block-by-block basis.

Adaptive loop filtering is filtering for reducing noise in a targetpixel by using pixel values surrounding the target pixel.

Adaptive offset is processing performed for each block to add orsubtract an offset value to or from a plurality of pixels included inthe block.

Hereinafter, descriptions are given of the moving picture codingapparatus 100 and the moving picture decoding apparatus 200 in thesecases.

FIG. 15 is a flowchart of the moving picture coding method according toa variation of this embodiment.

First, the moving picture coding apparatus 100 determines a predictionmode for a current block to be processed (S301). This prediction mode isone of the IPCM mode and the non-IPCM mode.

Next, the moving picture coding apparatus 100 writes the determinedprediction mode in the coded bit stream 132 (S302). In other words, thevariable length coding unit 111 generates the coded bit stream 132 (thecoded signal 131) including the determined prediction mode.

Next, the moving picture coding apparatus 100 determines whether or notthe prediction mode is the IPCM mode (S303). When the prediction mode isthe IPCM mode (Yes in S303), the moving picture coding apparatus 100stores the input image signal 120 in the memory 109 as a referencepicture for use in inter or intra prediction (S306).

When the prediction mode is the non-IPCM mode (No in S303), the movingpicture coding apparatus 100 generates a decoded image signal 126 byreconstructing the blocks of an image sample based on the predictionmode (S304). Next, the moving picture coding apparatus 100 processes thedecoded image signal 126 to generate an image signal 128 (S305). Thisprocessing includes at least one of deblocking filtering, adaptive loopfiltering, and adaptive offset. Next, the moving picture codingapparatus 100 stores the generated image signal 128 in the memory 109 asthe reference picture (S306).

FIG. 16 is a flowchart of the moving picture decoding method accordingto a variation of this embodiment.

First, the moving picture decoding apparatus 200 parses a coded bitstream 232 so as to obtain the prediction mode for the current blockincluded in the coded bit stream 232 (S311). This prediction mode is oneof the IPCM mode and the non-IPCM mode.

Next, the moving picture decoding apparatus 200 determine whether or notthe prediction mode is the IPCM mode (S312). When the prediction mode isthe IPCM mode (Yes in S312), the moving picture decoding apparatus 200stores the image signal of the current block included in the coded bitstream 232 in the memory 209 as a reference picture for use in inter orintra prediction (S315).

When the prediction mode is the non-IPCM mode (No in S312), the movingpicture decoding apparatus 200 generates a decoded image signal 226 byreconstructing the blocks of an image sample based on the predictionmode (S313). Next, the moving picture decoding apparatus 200 processesthe decoded image signal 226 to generate an image signal 228 (S314).This processing includes at least one of deblocking filtering, adaptiveloop filtering, and adaptive offset. Next, the moving picture decodingapparatus 200 stores the generated image signal 228 in the memory 209 asthe reference picture (S315).

[Embodiment 2]

A filtering method according to this embodiment is to determine aquantization parameter for an IPCM block using a quantization parameterfor a non-IPCM block, in deblocking filtering that is performed on theboundary between the IPCM block and the non-IPCM block. For example,according to the filtering method, the value of the quantizationparameter for the IPCM block is set to be the same value as the value ofthe quantization parameter for the non-IPCM block. In this way,according to the filtering method, it is possible to perform filteringusing an appropriate filter strength on the boundary between the IPCMblock and the non-IPCM block.

Hereinafter, differences from Embodiment 1 are mainly described, and thesame descriptions are not repeated.

FIG. 17 is a block diagram of a moving picture coding apparatus 400according to this embodiment. The moving picture coding apparatus 400shown in FIG. 17 performs deblocking filtering on the boundary betweenan IPCM block and a non-IPCM block adjacent to each other in an image.The moving picture coding apparatus 400 includes: a first quantizationparameter determining unit 401; a second quantization parameterdetermining unit 402; a filter strength determining unit 403; and afilter unit 404. The first quantization parameter determining unit 401,the second quantization parameter determining unit 402, the filterstrength determining unit 403, and the filter unit 404 are included in,for example, the filtering unit 115 or the filter unit 107 shown in FIG.6. In addition, the moving picture coding apparatus 400 may furtherinclude some or all of the plurality of processing units of the movingpicture coding apparatus 100 shown in FIG. 6.

FIG. 18 is a block diagram of a moving picture decoding apparatus 500according to this embodiment. The moving picture decoding apparatus 500shown in FIG. 18 performs deblocking filtering on the boundary betweenan IPCM block and a non-IPCM block adjacent to each other in an image.The moving picture decoding apparatus 500 includes: a first quantizationparameter determining unit 501; a second quantization parameterdetermining unit 502; a filter strength determining unit 503; and afilter unit 504. The first quantization parameter determining unit 501,the second quantization parameter determining unit 502, the filterstrength determining unit 503, and the filter unit 504 are included in,for example, the filtering unit 215 or the filter unit 207 shown in FIG.9. In addition, the moving picture decoding apparatus 500 may furtherinclude some or all of the plurality of processing units of the movingpicture decoding apparatus 200 shown in FIG. 9.

The moving picture coding apparatus 400 and the moving picture decodingapparatus 500 perform similar filtering, and thus the filtering by themoving picture coding apparatus 400 is described below as arepresentative.

FIG. 19 is a flowchart of a filtering method performed by the movingpicture coding apparatus 400 according to this embodiment.

First, the first quantization parameter determining unit 401 determinesa first quantization parameter 411 for a non-IPCM block (S301). Forexample, the first quantization parameter determining unit 401 obtains,as the first quantization parameter 411, the quantization parameter forthe non-IPCM block used by the quantization unit 103 or the inversequantization unit 104. Likewise, the first quantization parameterdetermining unit 401 obtains, as the first quantization parameter 411,for example, the quantization parameter for the non-IPCM block used bythe inverse quantization unit 204.

Next, the second quantization parameter determining unit 402 determinesa second quantization parameter 412 for determining a filter strengthfor an IPCM block, using the first quantization parameter 411 (S302).For example, the second quantization parameter determining unit 402determines the second quantization parameter 412 to be the same value asthe first quantization parameter 411.

Next, the filter strength determining unit 403 determines a filterstrength 413 using the first quantization parameter 411 and the secondquantization parameter 412 (S303). For example, the filter strengthdetermining unit 403 calculates an average value of the firstquantization parameter 411 and the second quantization parameter 412,and determines the filter strength 413 using the calculated averagevalue.

Lastly, the filter unit 404 performs deblocking filtering on theboundary between the non-IPCM block and the IPCM block using thedetermined filter strength 413 (S304).

Hereinafter, a specific example of this filtering is described.

FIG. 20 is a flowchart of an example of filtering according to thisembodiment.

First, the moving picture coding apparatus 400 sets a parameter i to aninitial value zero (S411). Next, the moving picture coding apparatus 400determines whether or not the parameter i is 1 or larger (S412).

When the parameter i is 1 or smaller (Yes in S412), the moving picturecoding apparatus 400 determines whether or not a block [i] is an IPCMblock (S413). Here, the following processing is performed on i=0 and 1,that are, a block [0] and a block [1]. Here, the block [0] and the block[1] are two blocks adjacent to each other, and share the boundary onwhich deblocking filtering is performed.

When the block [i] is a non-IPCM block (No in S413), the firstquantization parameter determining unit 401 calculates a quantizationparameter qP [i] using the following Expression 2 (S414).qP[i]=QPy[i]  (Expression 2)

Here, the quantization parameter QPy is a quantization parameter for aluminance component used in a quantization process, and a quantizationparameter qP is a parameter for calculating a filter strength. In otherwords, the first quantization parameter determining unit 401 sets, tothe quantization parameter qP [i] for the non-IPCM block, thequantization parameter used in the quantization process on the luminancecomponent of the non-IPCM block.

When the block [i] is an IPCM block (Yes in S413), the secondquantization parameter determining unit 402 calculates a quantizationparameter qP [i] using the following Expression 3 (S415).qP[i]=QPy[(i+1)%2]  (Expression 3)

Expression 3 is qP [0]=QPy [1] when i=0, and qP [1]=QPy [0] when i=1. Inother words, the second quantization parameter determining unit 402sets, to the quantization parameter qP [i] for the IPCM block, thequantization parameter used in the quantization process on the luminancecomponent of the non-IPCM block.

Next, the moving picture coding apparatus 400 adds “1” to the parameteri, and performs the processes starting with Step S412. Morespecifically, Steps S413 to S415 are executed on each of the block [0]and the block [1]. In this way, the quantization parameter qP [0] forthe block [0] and the quantization parameter qP [1] for the block [1]are calculated.

When the sequential processes are completed, the parameter i is set to“2” in Step S416. In this case (No in S412), the filter strengthdetermining unit 403 next calculates a parameter qPav for determining afilter strength, using the following Expression 4 (S417).qPav=(qP[0]+qP[1]+1)>>1  (Expression 4)

In other words, the filter strength determining unit 403 sets theparameter qPav to the average value between qP [0] and qP [1].

Lastly, the filter strength determining unit 403 determines a filterstrength 413 using the parameter qPav. Here, as a method for determiningthe filter strength 413, it is possible to use, for example, the methoddescribed in Embodiment 1.

It is assumed here that the block [0] is a non-IPCM block, and the block[1] is an IPCM block. In this case, qPav=qPy [0]+qPy [1]+1>>1=QP [0]+QPy[0]+1>>1=QPy [0]. In other words, the parameter qPav that is the filterstrength 413 is determined using only the quantization parameter for theluminance component of the non-IPCM block (the block [0]).

As described above, the moving picture coding apparatus 400 according tothis embodiment can prevent a small filter strength from being set forthe boundary between such an IPCM block and a non-IPCM block. In thisway, the moving picture coding apparatus 400 is capable of performingfiltering using an appropriate filter strength on the boundary betweenthe IPCM block and the non-IPCM block.

The filtering by the moving picture decoding apparatus 500 is similar tothe filtering by the moving picture coding apparatus 400. Morespecifically, the filtering by the moving picture decoding apparatus 500is explained by reading the above description of the filtering by themoving picture coding apparatus 400 such that the first quantizationparameter determining unit 401, the second quantization parameterdetermining unit 402, the filter strength determining unit 403, thefilter unit 404, the first quantization parameter 411, the secondquantization parameter 412, and the filter strength 413 are respectivelyreplaced with the first quantization parameter determining unit 501, thesecond quantization parameter determining unit 502, the filter strengthdetermining unit 503, the filter unit 504, the first quantizationparameter 511, the second quantization parameter 512, and the filterstrength 513.

In addition, the second quantization parameter determining unit 502 ofthe moving picture decoding apparatus 500 may determine the secondquantization parameter 512 using the first quantization parameter 511according to a delta QP (ΔQP). Here, the ΔQP is difference informationindicating the difference between the quantization parameter for theblock that is located immediately before a current block to be processedin processing order (coding order or decoding order) and thequantization parameter for the current block. In other words, when theΔQP is zero, the second quantization parameter 412 for the IPCM block isset to the same value as the value of the first quantization parameter411 for the non-IPCM block.

Hereinafter, descriptions are given of a flow of the processes of themoving picture coding method and a flow of the processes of the movingpicture decoding method in both of which the ΔQP is used.

FIG. 21 is a flowchart of the moving picture coding method according toa variation of this embodiment. The processes shown in FIG. 21 furtherinclude Steps S421 and S422, in addition to the processes shown in FIG.19.

In Step S421, the moving picture coding apparatus 400 sets the ΔQP forthe IPCM block to “0”. Next, the moving picture coding apparatus 400generates a coded bit stream including ΔQP (S422).

In addition, FIG. 22 is a flowchart of the moving picture decodingmethod according to the variation of this embodiment. Compared to theprocesses shown in FIG. 19, the processes shown in FIG. 22 furtherinclude Step S431, and includes Step S402A instead of Step S402.

In Step S431, the moving picture decoding apparatus 500 parses the codedbit stream to obtain the ΔQP included in the coded bit stream.

In Step S402A, the second quantization parameter determining unit 502determines the second quantization parameter 512 using the firstquantization parameter 511 according to the ΔQP. Here, when the currentblock to be processed is an IPCM block, the ΔQP is set to “0”. Thus,according to the ΔQP, the second quantization parameter determining unit502 sets the second quantization parameter 512 to the same value as thevalue of the quantization parameter for the block that is locatedimmediately before the current block in the processing order.

In other words, when the block located immediately before the processingorder is a non-IPCM block, the second quantization parameter for theIPCM block is set to the same value as the value of the firstquantization parameter for the non-IPCM block as in the above-describedprocessing. In other words, for the boundary between the IPCM block andthe left adjacent non-IPCM block, the quantization parameter for theIPCM block is set to the same value as the value of the quantizationparameter for the non-IPCM block. On the other hand, for each of theboundaries above, right, and below the IPCM block, the quantizationparameter for the IPCM block is not always set to the same value as thevalue of the quantization parameter for the non-IPCM block. However, thequantization parameter for the IPCM block is set to the same value asthe value of the quantization parameter for the right adjacent block andthe value is generally not zero. Thus, the filter strength set in thiscase is larger than a filter strength that is set in the case of fixedlysetting the quantization parameter for the IPCM block to zero. In thiscase, it is possible to set an appropriate filter strength for theboundary between the IPCM block and the non-IPCM block by setting theΔQP for the non-IPCM block to “0”.

Here, the difference information indicating that the ΔQP is “0” andincluded in the coded bit stream may be information for allowing themoving picture decoding apparatus 500 to determine that the ΔQP is “0”.In other words, the difference information may be a parameter explicitlyindicating that the ΔQP is “0” or may be another parameter. For example,it is also possible to specify that “ΔQP is assumed to be 0 when theparameter ΔQP is not included in the coded bit stream”. In this case,the moving picture coding apparatus 400 generates a coded bit streamwithout the parameter ΔQP for the IPCM block. In addition, the movingpicture decoding apparatus 500 assumes that the ΔQP is zero when thecoded bit stream does not include the parameter ΔQP.

The filtering methods, the moving picture coding method, the movingpicture decoding method, the moving picture coding apparatuses, and themoving picture decoding apparatuses have been described above based onthe non-limiting and exemplary embodiments and the variations thereof.

For example, it is also possible to combine at least parts of functionsof the filtering methods, moving picture coding method, moving picturedecoding method, moving picture coding apparatuses, moving picturedecoding apparatuses according to the embodiments and the variationsthereof.

In addition, the division of functional blocks in each of the blockdiagrams is exemplary. It is also possible to implement some of thefunctional blocks as a functional block, divide a functional block intoplural blocks, and/or move part of the function(s) to any of thefunctional blocks. In addition, the functions of the plural functionalblocks having functions similar to each other may be exerted in parallelor in time division by hardware or software.

In addition, the execution order of the plural steps of each of thefiltering methods is provided as a specific example, and thus otherorders are also possible. In addition, part of the steps may be executedsimultaneously with (in parallel to) any of the other steps.

For example, the order of Steps S201 and S202 shown in FIG. 5 is notlimited to the described order. In other words, it is only necessarythat Steps S204 and S205 are executed as a result when “one of twoblocks across a boundary is included in an IPCM block, and the other isnot included in an IPCM block”. In addition, the order of Steps S204 andS205 may also be arbitrary.

Likewise, the order of Steps S222 to S225 shown in FIG. 11 is notlimited to the described order. More specifically, the order of StepsS222 to S225 may be arbitrary as long as Step S224 is after Step S222and Step S225 is after S223.

[Embodiment 3]

The processing described in each of embodiments can be simplyimplemented in an independent computer system, by recording, in arecording medium, a program for implementing the configurations of themoving picture coding method (image coding method) and the movingpicture decoding method (image decoding method) described in each ofembodiments. The recording media may be any recording media as long asthe program can be recorded, such as a magnetic disk, an optical disk, amagnetic optical disk, an IC card, and a semiconductor memory.

Hereinafter, the applications to the moving picture coding method (imagecoding method) and the moving picture decoding method (image decodingmethod) described in each of embodiments and systems using thereof willbe described. The system has a feature of having an image coding anddecoding apparatus that includes an image coding apparatus using theimage coding method and an image decoding apparatus using the imagedecoding method. Other configurations in the system can be changed asappropriate depending on the cases.

FIG. 23 illustrates an overall configuration of a content providingsystem ex100 for implementing content distribution services. The areafor providing communication services is divided into cells of desiredsize, and base stations ex106, ex107, ex108, ex109, and ex110 which arefixed wireless stations are placed in each of the cells.

The content providing system ex100 is connected to devices, such as acomputer ex111, a personal digital assistant (PDA) ex112, a cameraex113, a cellular phone ex114 and a game machine ex115, via the Internetex101, an Internet service provider ex102, a telephone network ex104, aswell as the base stations ex106 to ex110, respectively.

However, the configuration of the content providing system ex100 is notlimited to the configuration shown in FIG. 23, and a combination inwhich any of the elements are connected is acceptable. In addition, eachdevice may be directly connected to the telephone network ex104, ratherthan via the base stations ex106 to ex110 which are the fixed wirelessstations. Furthermore, the devices may be interconnected to each othervia a short distance wireless communication and others.

The camera ex113, such as a digital video camera, is capable ofcapturing video. A camera ex116, such as a digital camera, is capable ofcapturing both still images and video. Furthermore, the cellular phoneex114 may be the one that meets any of the standards such as GlobalSystem for Mobile Communications (GSM) (registered trademark), CodeDivision Multiple Access (CDMA), Wideband-Code Division Multiple Access(W-CDMA), Long Term Evolution (LTE), and High Speed Packet Access(HSPA). Alternatively, the cellular phone ex114 may be a PersonalHandyphone System (PHS).

In the content providing system ex100, a streaming server ex103 isconnected to the camera ex113 and others via the telephone network ex104and the base station ex109, which enables distribution of images of alive show and others. In such a distribution, a content (for example,video of a music live show) captured by the user using the camera ex113is coded as described above in each of embodiments (i.e., the camerafunctions as the image coding apparatus according to an aspect of thepresent invention), and the coded content is transmitted to thestreaming server ex103. On the other hand, the streaming server ex103carries out stream distribution of the transmitted content data to theclients upon their requests. The clients include the computer ex111, thePDA ex112, the camera ex113, the cellular phone ex114, and the gamemachine ex115 that are capable of decoding the above-mentioned codeddata. Each of the devices that have received the distributed datadecodes and reproduces the coded data (i.e., functions as the imagedecoding apparatus according to an aspect of the present invention).

The captured data may be coded by the camera ex113 or the streamingserver ex103 that transmits the data, or the coding processes may beshared between the camera ex113 and the streaming server ex103.Similarly, the distributed data may be decoded by the clients or thestreaming server ex103, or the decoding processes may be shared betweenthe clients and the streaming server ex103. Furthermore, the data of thestill images and video captured by not only the camera ex113 but alsothe camera ex116 may be transmitted to the streaming server ex103through the computer ex111. The coding processes may be performed by thecamera ex116, the computer ex111, or the streaming server ex103, orshared among them.

Furthermore, the coding and decoding processes may be performed by anLSI ex500 generally included in each of the computer ex111 and thedevices. The LSI ex500 may be configured of a single chip or a pluralityof chips. Software for coding and decoding video may be integrated intosome type of a recording medium (such as a CD-ROM, a flexible disk, anda hard disk) that is readable by the computer ex111 and others, and thecoding and decoding processes may be performed using the software.Furthermore, when the cellular phone ex114 is equipped with a camera,the video data obtained by the camera may be transmitted. The video datais data coded by the LSI ex500 included in the cellular phone ex114.

Furthermore, the streaming server ex103 may be composed of servers andcomputers, and may decentralize data and process the decentralized data,record, or distribute data.

As described above, the clients may receive and reproduce the coded datain the content providing system ex100. In other words, the clients canreceive and decode information transmitted by the user, and reproducethe decoded data in real time in the content providing system ex100, sothat the user who does not have any particular right and equipment canimplement personal broadcasting.

Aside from the example of the content providing system ex100, at leastone of the moving picture coding apparatus (image coding apparatus) andthe moving picture decoding apparatus (image decoding apparatus)described in each of embodiments may be implemented in a digitalbroadcasting system ex200 illustrated in FIG. 24. More specifically, abroadcast station ex201 communicates or transmits, via radio waves to abroadcast satellite ex202, multiplexed data obtained by multiplexingaudio data and others onto video data. The video data is data coded bythe moving picture coding method described in each of embodiments (i.e.,data coded by the image coding apparatus according to an aspect of thepresent invention). Upon receipt of the multiplexed data, the broadcastsatellite ex202 transmits radio waves for broadcasting. Then, a home-useantenna ex204 with a satellite broadcast reception function receives theradio waves. Next, a device such as a television (receiver) ex300 and aset top box (STB) ex217 decodes the received multiplexed data, andreproduces the decoded data (i.e., functions as the image decodingapparatus according to an aspect of the present invention).

Furthermore, a reader/recorder ex218 (i) reads and decodes themultiplexed data recorded on a recording medium ex215, such as a DVD anda BD, or (i) codes video signals in the recording medium ex215, and insome cases, writes data obtained by multiplexing an audio signal on thecoded data. The reader/recorder ex218 can include the moving picturedecoding apparatus or the moving picture coding apparatus as shown ineach of embodiments. In this case, the reproduced video signals aredisplayed on the monitor ex219, and can be reproduced by another deviceor system using the recording medium ex215 on which the multiplexed datais recorded. It is also possible to implement the moving picturedecoding apparatus in the set top box ex217 connected to the cable ex203for a cable television or to the antenna ex204 for satellite and/orterrestrial broadcasting, so as to display the video signals on themonitor ex219 of the television ex300. The moving picture decodingapparatus may be implemented not in the set top box but in thetelevision ex300.

FIG. 25 illustrates the television (receiver) ex300 that uses the movingpicture coding method and the moving picture decoding method describedin each of embodiments. The television ex300 includes: a tuner ex301that obtains or provides multiplexed data obtained by multiplexing audiodata onto video data, through the antenna ex204 or the cable ex203, etc.that receives a broadcast; a modulation/demodulation unit ex302 thatdemodulates the received multiplexed data or modulates data intomultiplexed data to be supplied outside; and amultiplexing/demultiplexing unit ex303 that demultiplexes the modulatedmultiplexed data into video data and audio data, or multiplexes videodata and audio data coded by a signal processing unit ex306 into data.

The television ex300 further includes: a signal processing unit ex306including an audio signal processing unit ex304 and a video signalprocessing unit ex305 that decode audio data and video data and codeaudio data and video data, respectively (which function as the imagecoding apparatus and the image decoding apparatus according to theaspects of the present invention); and an output unit ex309 including aspeaker ex307 that provides the decoded audio signal, and a display unitex308 that displays the decoded video signal, such as a display.Furthermore, the television ex300 includes an interface unit ex317including an operation input unit ex312 that receives an input of a useroperation. Furthermore, the television ex300 includes a control unitex310 that controls overall each constituent element of the televisionex300, and a power supply circuit unit ex311 that supplies power to eachof the elements. Other than the operation input unit ex312, theinterface unit ex317 may include: a bridge ex313 that is connected to anexternal device, such as the reader/recorder ex218; a slot unit ex314for enabling attachment of the recording medium ex216, such as an SDcard; a driver ex315 to be connected to an external recording medium,such as a hard disk; and a modem ex316 to be connected to a telephonenetwork. Here, the recording medium ex216 can electrically recordinformation using a non-volatile/volatile semiconductor memory elementfor storage. The constituent elements of the television ex300 areconnected to each other through a synchronous bus.

First, the configuration in which the television ex300 decodesmultiplexed data obtained from outside through the antenna ex204 andothers and reproduces the decoded data will be described. In thetelevision ex300, upon a user operation through a remote controllerex220 and others, the multiplexing/demultiplexing unit ex303demultiplexes the multiplexed data demodulated by themodulation/demodulation unit ex302, under control of the control unitex310 including a CPU. Furthermore, the audio signal processing unitex304 decodes the demultiplexed audio data, and the video signalprocessing unit ex305 decodes the demultiplexed video data, using thedecoding method described in each of embodiments, in the televisionex300. The output unit ex309 provides the decoded video signal and audiosignal outside, respectively. When the output unit ex309 provides thevideo signal and the audio signal, the signals may be temporarily storedin buffers ex318 and ex319, and others so that the signals arereproduced in synchronization with each other. Furthermore, thetelevision ex300 may read multiplexed data not through a broadcast andothers but from the recording media ex215 and ex216, such as a magneticdisk, an optical disk, and a SD card. Next, a configuration in which thetelevision ex300 codes an audio signal and a video signal, and transmitsthe data outside or writes the data on a recording medium will bedescribed. In the television ex300, upon a user operation through theremote controller ex220 and others, the audio signal processing unitex304 codes an audio signal, and the video signal processing unit ex305codes a video signal, under control of the control unit ex310 using thecoding method described in each of embodiments. Themultiplexing/demultiplexing unit ex303 multiplexes the coded videosignal and audio signal, and provides the resulting signal outside. Whenthe multiplexing/demultiplexing unit ex303 multiplexes the video signaland the audio signal, the signals may be temporarily stored in thebuffers ex320 and ex321, and others so that the signals are reproducedin synchronization with each other. Here, the buffers ex318, ex319,ex320, and ex321 may be plural as illustrated, or at least one buffermay be shared in the television ex300. Furthermore, data may be storedin a buffer so that the system overflow and underflow may be avoidedbetween the modulation/demodulation unit ex302 and themultiplexing/demultiplexing unit ex303, for example.

Furthermore, the television ex300 may include a configuration forreceiving an AV input from a microphone or a camera other than theconfiguration for obtaining audio and video data from a broadcast or arecording medium, and may code the obtained data. Although thetelevision ex300 can code, multiplex, and provide outside data in thedescription, it may be capable of only receiving, decoding, andproviding outside data but not the coding, multiplexing, and providingoutside data.

Furthermore, when the reader/recorder ex218 reads or writes multiplexeddata from or on a recording medium, one of the television ex300 and thereader/recorder ex218 may decode or code the multiplexed data, and thetelevision ex300 and the reader/recorder ex218 may share the decoding orcoding.

As an example, FIG. 26 illustrates a configuration of an informationreproducing/recording unit ex400 when data is read or written from or onan optical disk. The information reproducing/recording unit ex400includes constituent elements ex401, ex402, ex403, ex404, ex405, ex406,and ex407 to be described hereinafter. The optical head ex401 irradiatesa laser spot in a recording surface of the recording medium ex215 thatis an optical disk to write information, and detects reflected lightfrom the recording surface of the recording medium ex215 to read theinformation. The modulation recording unit ex402 electrically drives asemiconductor laser included in the optical head ex401, and modulatesthe laser light according to recorded data. The reproductiondemodulating unit ex403 amplifies a reproduction signal obtained byelectrically detecting the reflected light from the recording surfaceusing a photo detector included in the optical head ex401, anddemodulates the reproduction signal by separating a signal componentrecorded on the recording medium ex215 to reproduce the necessaryinformation. The buffer ex404 temporarily holds the information to berecorded on the recording medium ex215 and the information reproducedfrom the recording medium ex215. The disk motor ex405 rotates therecording medium ex215. The servo control unit ex406 moves the opticalhead ex401 to a predetermined information track while controlling therotation drive of the disk motor ex405 so as to follow the laser spot.The system control unit ex407 controls overall the informationreproducing/recording unit ex400. The reading and writing processes canbe implemented by the system control unit ex407 using variousinformation stored in the buffer ex404 and generating and adding newinformation as necessary, and by the modulation recording unit ex402,the reproduction demodulating unit ex403, and the servo control unitex406 that record and reproduce information through the optical headex401 while being operated in a coordinated manner. The system controlunit ex407 includes, for example, a microprocessor, and executesprocessing by causing a computer to execute a program for read andwrite.

Although the optical head ex401 irradiates a laser spot in thedescription, it may perform high-density recording using near fieldlight.

FIG. 27 illustrates the recording medium ex215 that is the optical disk.On the recording surface of the recording medium ex215, guide groovesare spirally formed, and an information track ex230 records, in advance,address information indicating an absolute position on the diskaccording to change in a shape of the guide grooves. The addressinformation includes information for determining positions of recordingblocks ex231 that are a unit for recording data. Reproducing theinformation track ex230 and reading the address information in anapparatus that records and reproduces data can lead to determination ofthe positions of the recording blocks. Furthermore, the recording mediumex215 includes a data recording area ex233, an inner circumference areaex232, and an outer circumference area ex234. The data recording areaex233 is an area for use in recording the user data. The innercircumference area ex232 and the outer circumference area ex234 that areinside and outside of the data recording area ex233, respectively arefor specific use except for recording the user data. The informationreproducing/recording unit 400 reads and writes coded audio, coded videodata, or multiplexed data obtained by multiplexing the coded audio andvideo data, from and on the data recording area ex233 of the recordingmedium ex215.

Although an optical disk having a layer, such as a DVD and a BD isdescribed as an example in the description, the optical disk is notlimited to such, and may be an optical disk having a multilayerstructure and capable of being recorded on a part other than thesurface. Furthermore, the optical disk may have a structure formultidimensional recording/reproduction, such as recording ofinformation using light of colors with different wavelengths in the sameportion of the optical disk and for recording information havingdifferent layers from various angles.

Furthermore, a car ex210 having an antenna ex205 can receive data fromthe satellite ex202 and others, and reproduce video on a display devicesuch as a car navigation system ex211 set in the car ex210, in thedigital broadcasting system ex200. Here, a configuration of the carnavigation system ex211 will be a configuration, for example, includinga GPS receiving unit from the configuration illustrated in FIG. 25. Thesame will be true for the configuration of the computer ex111, thecellular phone ex114, and others.

FIG. 28A illustrates the cellular phone ex114 that uses the movingpicture coding method and the moving picture decoding method describedin embodiments. The cellular phone ex114 includes: an antenna ex350 fortransmitting and receiving radio waves through the base station ex110; acamera unit ex365 capable of capturing moving and still images; and adisplay unit ex358 such as a liquid crystal display for displaying thedata such as decoded video captured by the camera unit ex365 or receivedby the antenna ex350. The cellular phone ex114 further includes: a mainbody unit including an operation key unit ex366; an audio output unitex357 such as a speaker for output of audio; an audio input unit ex356such as a microphone for input of audio; a memory unit ex367 for storingcaptured video or still pictures, recorded audio, coded or decoded dataof the received video, the still pictures, e-mails, or others; and aslot unit ex364 that is an interface unit for a recording medium thatstores data in the same manner as the memory unit ex367.

Next, an example of a configuration of the cellular phone ex114 will bedescribed with reference to FIG. 28B. In the cellular phone ex114, amain control unit ex360 designed to control overall each unit of themain body including the display unit ex358 as well as the operation keyunit ex366 is connected mutually, via a synchronous bus ex370, to apower supply circuit unit ex361, an operation input control unit ex362,a video signal processing unit ex355, a camera interface unit ex363, aliquid crystal display (LCD) control unit ex359, amodulation/demodulation unit ex352, a multiplexing/demultiplexing unitex353, an audio signal processing unit ex354, the slot unit ex364, andthe memory unit ex367.

When a call-end key or a power key is turned ON by a user's operation,the power supply circuit unit ex361 supplies the respective units withpower from a battery pack so as to activate the cell phone ex114.

In the cellular phone ex114, the audio signal processing unit ex354converts the audio signals collected by the audio input unit ex356 invoice conversation mode into digital audio signals under the control ofthe main control unit ex360 including a CPU, ROM, and RAM. Then, themodulation/demodulation unit ex352 performs spread spectrum processingon the digital audio signals, and the transmitting and receiving unitex351 performs digital-to-analog conversion and frequency conversion onthe data, so as to transmit the resulting data via the antenna ex350.Also, in the cellular phone ex114, the transmitting and receiving unitex351 amplifies the data received by the antenna ex350 in voiceconversation mode and performs frequency conversion and theanalog-to-digital conversion on the data. Then, themodulation/demodulation unit ex352 performs inverse spread spectrumprocessing on the data, and the audio signal processing unit ex354converts it into analog audio signals, so as to output them via theaudio output unit ex357.

Furthermore, when an e-mail in data communication mode is transmitted,text data of the e-mail inputted by operating the operation key unitex366 and others of the main body is sent out to the main control unitex360 via the operation input control unit ex362. The main control unitex360 causes the modulation/demodulation unit ex352 to perform spreadspectrum processing on the text data, and the transmitting and receivingunit ex351 performs the digital-to-analog conversion and the frequencyconversion on the resulting data to transmit the data to the basestation ex110 via the antenna ex350. When an e-mail is received,processing that is approximately inverse to the processing fortransmitting an e-mail is performed on the received data, and theresulting data is provided to the display unit ex358.

When video, still images, or video and audio in data communication modeis or are transmitted, the video signal processing unit ex355 compressesand codes video signals supplied from the camera unit ex365 using themoving picture coding method shown in each of embodiments (i.e.,functions as the image coding apparatus according to the aspect of thepresent invention), and transmits the coded video data to themultiplexing/demultiplexing unit ex353. In contrast, during when thecamera unit ex365 captures video, still images, and others, the audiosignal processing unit ex354 codes audio signals collected by the audioinput unit ex356, and transmits the coded audio data to themultiplexing/demultiplexing unit ex353.

The multiplexing/demultiplexing unit ex353 multiplexes the coded videodata supplied from the video signal processing unit ex355 and the codedaudio data supplied from the audio signal processing unit ex354, using apredetermined method. Then, the modulation/demodulation unit(modulation/demodulation circuit unit) ex352 performs spread spectrumprocessing on the multiplexed data, and the transmitting and receivingunit ex351 performs digital-to-analog conversion and frequencyconversion on the data so as to transmit the resulting data via theantenna ex350.

When receiving data of a video file which is linked to a Web page andothers in data communication mode or when receiving an e-mail with videoand/or audio attached, in order to decode the multiplexed data receivedvia the antenna ex350, the multiplexing/demultiplexing unit ex353demultiplexes the multiplexed data into a video data bit stream and anaudio data bit stream, and supplies the video signal processing unitex355 with the coded video data and the audio signal processing unitex354 with the coded audio data, through the synchronous bus ex370. Thevideo signal processing unit ex355 decodes the video signal using amoving picture decoding method corresponding to the moving picturecoding method shown in each of embodiments (i.e., functions as the imagedecoding apparatus according to the aspect of the present invention),and then the display unit ex358 displays, for instance, the video andstill images included in the video file linked to the Web page via theLCD control unit ex359. Furthermore, the audio signal processing unitex354 decodes the audio signal, and the audio output unit ex357 providesthe audio.

Furthermore, similarly to the television ex300, a terminal such as thecellular phone ex114 probably have 3 types of implementationconfigurations including not only (i) a transmitting and receivingterminal including both a coding apparatus and a decoding apparatus, butalso (ii) a transmitting terminal including only a coding apparatus and(iii) a receiving terminal including only a decoding apparatus. Althoughthe digital broadcasting system ex200 receives and transmits themultiplexed data obtained by multiplexing audio data onto video data inthe description, the multiplexed data may be data obtained bymultiplexing not audio data but character data related to video ontovideo data, and may be not multiplexed data but video data itself.

As such, the moving picture coding method and the moving picturedecoding method in each of embodiments can be used in any of the devicesand systems described. Thus, the advantages described in each ofembodiments can be obtained.

Furthermore, the present invention is not limited to embodiments, andvarious modifications and revisions are possible without departing fromthe scope of the present invention.

[Embodiment 4]

Video data can be generated by switching, as necessary, between (i) themoving picture coding method or the moving picture coding apparatusshown in each of embodiments and (ii) a moving picture coding method ora moving picture coding apparatus in conformity with a differentstandard, such as MPEG-2, MPEG-4 AVC, and VC-1.

Here, when a plurality of video data that conforms to the differentstandards is generated and is then decoded, the decoding methods need tobe selected to conform to the different standards. However, since towhich standard each of the plurality of the video data to be decodedconform cannot be detected, there is a problem that an appropriatedecoding method cannot be selected.

In order to solve the problem, multiplexed data obtained by multiplexingaudio data and others onto video data has a structure includingidentification information indicating to which standard the video dataconforms. The specific structure of the multiplexed data including thevideo data generated in the moving picture coding method and by themoving picture coding apparatus shown in each of embodiments will behereinafter described. The multiplexed data is a digital stream in theMPEG-2 Transport Stream format.

FIG. 29 illustrates a structure of the multiplexed data. As illustratedin FIG. 29, the multiplexed data can be obtained by multiplexing atleast one of a video stream, an audio stream, a presentation graphicsstream (PG), and an interactive graphics stream. The video streamrepresents primary video and secondary video of a movie, the audiostream (IG) represents a primary audio part and a secondary audio partto be mixed with the primary audio part, and the presentation graphicsstream represents subtitles of the movie. Here, the primary video isnormal video to be displayed on a screen, and the secondary video isvideo to be displayed on a smaller window in the primary video.Furthermore, the interactive graphics stream represents an interactivescreen to be generated by arranging the GUI components on a screen. Thevideo stream is coded in the moving picture coding method or by themoving picture coding apparatus shown in each of embodiments, or in amoving picture coding method or by a moving picture coding apparatus inconformity with a conventional standard, such as MPEG-2, MPEG-4 AVC, andVC-1. The audio stream is coded in accordance with a standard, such asDolby-AC-3, Dolby Digital Plus, MLP, DTS, DTS-HD, and linear PCM.

Each stream included in the multiplexed data is identified by PID. Forexample, 0x1011 is allocated to the video stream to be used for video ofa movie, 0x1100 to 0x111F are allocated to the audio streams, 0x1200 to0x121F are allocated to the presentation graphics streams, 0x1400 to0x141F are allocated to the interactive graphics streams, 0x1B00 to0x1B1F are allocated to the video streams to be used for secondary videoof the movie, and 0x1A00 to 0x1A1F are allocated to the audio streams tobe used for the secondary audio to be mixed with the primary audio.

FIG. 30 schematically illustrates how data is multiplexed. First, avideo stream ex235 composed of video frames and an audio stream ex238composed of audio frames are transformed into a stream of PES packetsex236 and a stream of PES packets ex239, and further into TS packetsex237 and TS packets ex240, respectively. Similarly, data of apresentation graphics stream ex241 and data of an interactive graphicsstream ex244 are transformed into a stream of PES packets ex242 and astream of PES packets ex245, and further into TS packets ex243 and TSpackets ex246, respectively. These TS packets are multiplexed into astream to obtain multiplexed data ex247.

FIG. 31 illustrates how a video stream is stored in a stream of PESpackets in more detail. The first bar in FIG. 31 shows a video framestream in a video stream. The second bar shows the stream of PESpackets. As indicated by arrows denoted as yy1, yy2, yy3, and yy4 inFIG. 31, the video stream is divided into pictures as I pictures, Bpictures, and P pictures each of which is a video presentation unit, andthe pictures are stored in a payload of each of the PES packets. Each ofthe PES packets has a PES header, and the PES header stores aPresentation Time-Stamp (PTS) indicating a display time of the picture,and a Decoding Time-Stamp (DTS) indicating a decoding time of thepicture.

FIG. 32 illustrates a format of TS packets to be finally written on themultiplexed data. Each of the TS packets is a 188-byte fixed lengthpacket including a 4-byte TS header having information, such as a PIDfor identifying a stream and a 184-byte TS payload for storing data. ThePES packets are divided, and stored in the TS payloads, respectively.When a BD ROM is used, each of the TS packets is given a 4-byteTP_Extra_Header, thus resulting in 192-byte source packets. The sourcepackets are written on the multiplexed data. The TP_Extra_Header storesinformation such as an Arrival_Time_Stamp (ATS). The ATS shows atransfer start time at which each of the TS packets is to be transferredto a PID filter. The source packets are arranged in the multiplexed dataas shown at the bottom of FIG. 32. The numbers incrementing from thehead of the multiplexed data are called source packet numbers (SPNs).

Each of the TS packets included in the multiplexed data includes notonly streams of audio, video, subtitles and others, but also a ProgramAssociation Table (PAT), a Program Map Table (PMT), and a Program ClockReference (PCR). The PAT shows what a PID in a PMT used in themultiplexed data indicates, and a PID of the PAT itself is registered aszero. The PMT stores PIDs of the streams of video, audio, subtitles andothers included in the multiplexed data, and attribute information ofthe streams corresponding to the PIDs. The PMT also has variousdescriptors relating to the multiplexed data. The descriptors haveinformation such as copy control information showing whether copying ofthe multiplexed data is permitted or not. The PCR stores STC timeinformation corresponding to an ATS showing when the PCR packet istransferred to a decoder, in order to achieve synchronization between anArrival Time Clock (ATC) that is a time axis of ATSs, and an System TimeClock (STC) that is a time axis of PTSs and DTSs.

FIG. 33 illustrates the data structure of the PMT in detail. A PMTheader is disposed at the top of the PMT. The PMT header describes thelength of data included in the PMT and others. A plurality ofdescriptors relating to the multiplexed data is disposed after the PMTheader. Information such as the copy control information is described inthe descriptors. After the descriptors, a plurality of pieces of streaminformation relating to the streams included in the multiplexed data isdisposed. Each piece of stream information includes stream descriptorseach describing information, such as a stream type for identifying acompression codec of a stream, a stream PID, and stream attributeinformation (such as a frame rate or an aspect ratio). The streamdescriptors are equal in number to the number of streams in themultiplexed data.

When the multiplexed data is recorded on a recording medium and others,it is recorded together with multiplexed data information files.

Each of the multiplexed data information files is management informationof the multiplexed data as shown in FIG. 34. The multiplexed datainformation files are in one to one correspondence with the multiplexeddata, and each of the files includes multiplexed data information,stream attribute information, and an entry map.

As illustrated in FIG. 34, the multiplexed data information includes asystem rate, a reproduction start time, and a reproduction end time. Thesystem rate indicates the maximum transfer rate at which a system targetdecoder to be described later transfers the multiplexed data to a PIDfilter. The intervals of the ATSs included in the multiplexed data areset to not higher than a system rate. The reproduction start timeindicates a PTS in a video frame at the head of the multiplexed data. Aninterval of one frame is added to a PTS in a video frame at the end ofthe multiplexed data, and the PTS is set to the reproduction end time.

As shown in FIG. 35, a piece of attribute information is registered inthe stream attribute information, for each PID of each stream includedin the multiplexed data. Each piece of attribute information hasdifferent information depending on whether the corresponding stream is avideo stream, an audio stream, a presentation graphics stream, or aninteractive graphics stream. Each piece of video stream attributeinformation carries information including what kind of compression codecis used for compressing the video stream, and the resolution, aspectratio and frame rate of the pieces of picture data that is included inthe video stream. Each piece of audio stream attribute informationcarries information including what kind of compression codec is used forcompressing the audio stream, how many channels are included in theaudio stream, which language the audio stream supports, and how high thesampling frequency is. The video stream attribute information and theaudio stream attribute information are used for initialization of adecoder before the player plays back the information.

In the present embodiment, the multiplexed data to be used is of astream type included in the PMT. Furthermore, when the multiplexed datais recorded on a recording medium, the video stream attributeinformation included in the multiplexed data information is used. Morespecifically, the moving picture coding method or the moving picturecoding apparatus described in each of embodiments includes a step or aunit for allocating unique information indicating video data generatedby the moving picture coding method or the moving picture codingapparatus in each of embodiments, to the stream type included in the PMTor the video stream attribute information. With the configuration, thevideo data generated by the moving picture coding method or the movingpicture coding apparatus described in each of embodiments can bedistinguished from video data that conforms to another standard.

Furthermore, FIG. 36 illustrates steps of the moving picture decodingmethod according to the present embodiment. In Step exS100, the streamtype included in the PMT or the video stream attribute informationincluded in the multiplexed data information is obtained from themultiplexed data. Next, in Step exS101, it is determined whether or notthe stream type or the video stream attribute information indicates thatthe multiplexed data is generated by the moving picture coding method orthe moving picture coding apparatus in each of embodiments. When it isdetermined that the stream type or the video stream attributeinformation indicates that the multiplexed data is generated by themoving picture coding method or the moving picture coding apparatus ineach of embodiments, in Step exS102, decoding is performed by the movingpicture decoding method in each of embodiments. Furthermore, when thestream type or the video stream attribute information indicatesconformance to the conventional standards, such as MPEG-2, MPEG-4 AVC,and VC-1, in Step exS103, decoding is performed by a moving picturedecoding method in conformity with the conventional standards.

As such, allocating a new unique value to the stream type or the videostream attribute information enables determination whether or not themoving picture decoding method or the moving picture decoding apparatusthat is described in each of embodiments can perform decoding. Even whenmultiplexed data that conforms to a different standard is input, anappropriate decoding method or apparatus can be selected. Thus, itbecomes possible to decode information without any error. Furthermore,the moving picture coding method or apparatus, or the moving picturedecoding method or apparatus in the present embodiment can be used inthe devices and systems described above.

[Embodiment 5]

Each of the moving picture coding method, the moving picture codingapparatus, the moving picture decoding method, and the moving picturedecoding apparatus in each of embodiments is typically achieved in theform of an integrated circuit or a Large Scale Integrated (LSI) circuit.As an example of the LSI, FIG. 37 illustrates a configuration of the LSIex500 that is made into one chip. The LSI ex500 includes elements ex501,ex502, ex503, ex504, ex505, ex506, ex507, ex508, and ex509 to bedescribed below, and the elements are connected to each other through abus ex510. The power supply circuit unit ex505 is activated by supplyingeach of the elements with power when the power supply circuit unit ex505is turned on.

For example, when coding is performed, the LSI ex500 receives an AVsignal from a microphone ex117, a camera ex113, and others through an AVIO ex509 under control of a control unit ex501 including a CPU ex502, amemory controller ex503, a stream controller ex504, and a drivingfrequency control unit ex512. The received AV signal is temporarilystored in an external memory ex511, such as an SDRAM. Under control ofthe control unit ex501, the stored data is segmented into data portionsaccording to the processing amount and speed to be transmitted to asignal processing unit ex507. Then, the signal processing unit ex507codes an audio signal and/or a video signal. Here, the coding of thevideo signal is the coding described in each of embodiments.Furthermore, the signal processing unit ex507 sometimes multiplexes thecoded audio data and the coded video data, and a stream IO ex506provides the multiplexed data outside. The provided multiplexed data istransmitted to the base station ex107, or written on the recordingmedium ex215. When data sets are multiplexed, the data should betemporarily stored in the buffer ex508 so that the data sets aresynchronized with each other.

Although the memory ex511 is an element outside the LSI ex500, it may beincluded in the LSI ex500. The buffer ex508 is not limited to onebuffer, but may be composed of buffers. Furthermore, the LSI ex500 maybe made into one chip or a plurality of chips.

Furthermore, although the control unit ex501 includes the CPU ex502, thememory controller ex503, the stream controller ex504, the drivingfrequency control unit ex512, the configuration of the control unitex501 is not limited to such. For example, the signal processing unitex507 may further include a CPU. Inclusion of another CPU in the signalprocessing unit ex507 can improve the processing speed. Furthermore, asanother example, the CPU ex502 may serve as or be a part of the signalprocessing unit ex507, and, for example, may include an audio signalprocessing unit. In such a case, the control unit ex501 includes thesignal processing unit ex507 or the CPU ex502 including a part of thesignal processing unit ex507.

The name used here is LSI, but it may also be called IC, system LSI,super LSI, or ultra LSI depending on the degree of integration.

Moreover, ways to achieve integration are not limited to the LSI, and aspecial circuit or a general purpose processor and so forth can alsoachieve the integration. Field Programmable Gate Array (FPGA) that canbe programmed after manufacturing LSIs or a reconfigurable processorthat allows re-configuration of the connection or configuration of anLSI can be used for the same purpose.

In the future, with advancement in semiconductor technology, a brand-newtechnology may replace LSI. The functional blocks can be integratedusing such a technology. The possibility is that the present inventionis applied to biotechnology.

[Embodiment 6]

When video data generated in the moving picture coding method or by themoving picture coding apparatus described in each of embodiments isdecoded, compared to when video data that conforms to a conventionalstandard, such as MPEG-2, MPEG-4 AVC, and VC-1 is decoded, theprocessing amount probably increases. Thus, the LSI ex500 needs to beset to a driving frequency higher than that of the CPU ex502 to be usedwhen video data in conformity with the conventional standard is decoded.However, when the driving frequency is set higher, there is a problemthat the power consumption increases.

In order to solve the problem, the moving picture decoding apparatus,such as the television ex300 and the LSI ex500 is configured todetermine to which standard the video data conforms, and switch betweenthe driving frequencies according to the determined standard. FIG. 38illustrates a configuration ex800 in the present embodiment. A drivingfrequency switching unit ex803 sets a driving frequency to a higherdriving frequency when video data is generated by the moving picturecoding method or the moving picture coding apparatus described in eachof embodiments. Then, the driving frequency switching unit ex803instructs a decoding processing unit ex801 that executes the movingpicture decoding method described in each of embodiments to decode thevideo data. When the video data conforms to the conventional standard,the driving frequency switching unit ex803 sets a driving frequency to alower driving frequency than that of the video data generated by themoving picture coding method or the moving picture coding apparatusdescribed in each of embodiments. Then, the driving frequency switchingunit ex803 instructs the decoding processing unit ex802 that conforms tothe conventional standard to decode the video data.

More specifically, the driving frequency switching unit ex803 includesthe CPU ex502 and the driving frequency control unit ex512 in FIG. 37.Here, each of the decoding processing unit ex801 that executes themoving picture decoding method described in each of embodiments and thedecoding processing unit ex802 that conforms to the conventionalstandard corresponds to the signal processing unit ex507 in FIG. 37. TheCPU ex502 determines to which standard the video data conforms. Then,the driving frequency control unit ex512 determines a driving frequencybased on a signal from the CPU ex502. Furthermore, the signal processingunit ex507 decodes the video data based on the signal from the CPUex502. For example, the identification information described inEmbodiment 4 is probably used for identifying the video data. Theidentification information is not limited to the one described inEmbodiment 4 but may be any information as long as the informationindicates to which standard the video data conforms. For example, whenwhich standard video data conforms to can be determined based on anexternal signal for determining that the video data is used for atelevision or a disk, etc., the determination may be made based on suchan external signal. Furthermore, the CPU ex502 selects a drivingfrequency based on, for example, a look-up table in which the standardsof the video data are associated with the driving frequencies as shownin FIG. 40. The driving frequency can be selected by storing the look-uptable in the buffer ex508 and in an internal memory of an LSI, and withreference to the look-up table by the CPU ex502.

FIG. 39 illustrates steps for executing a method in the presentembodiment. First, in Step exS200, the signal processing unit ex507obtains identification information from the multiplexed data. Next, inStep exS201, the CPU ex502 determines whether or not the video data isgenerated by the coding method and the coding apparatus described ineach of embodiments, based on the identification information. When thevideo data is generated by the moving picture coding method and themoving picture coding apparatus described in each of embodiments, inStep exS202, the CPU ex502 transmits a signal for setting the drivingfrequency to a higher driving frequency to the driving frequency controlunit ex512. Then, the driving frequency control unit ex512 sets thedriving frequency to the higher driving frequency. On the other hand,when the identification information indicates that the video dataconforms to the conventional standard, such as MPEG-2, MPEG-4 AVC, andVC-1, in Step exS203, the CPU ex502 transmits a signal for setting thedriving frequency to a lower driving frequency to the driving frequencycontrol unit ex512. Then, the driving frequency control unit ex512 setsthe driving frequency to the lower driving frequency than that in thecase where the video data is generated by the moving picture codingmethod and the moving picture coding apparatus described in each ofembodiment.

Furthermore, along with the switching of the driving frequencies, thepower conservation effect can be improved by changing the voltage to beapplied to the LSI ex500 or an apparatus including the LSI ex500. Forexample, when the driving frequency is set lower, the voltage to beapplied to the LSI ex500 or the apparatus including the LSI ex500 isprobably set to a voltage lower than that in the case where the drivingfrequency is set higher.

Furthermore, when the processing amount for decoding is larger, thedriving frequency may be set higher, and when the processing amount fordecoding is smaller, the driving frequency may be set lower as themethod for setting the driving frequency. Thus, the setting method isnot limited to the ones described above. For example, when theprocessing amount for decoding video data in conformity with MPEG-4 AVCis larger than the processing amount for decoding video data generatedby the moving picture coding method and the moving picture codingapparatus described in each of embodiments, the driving frequency isprobably set in reverse order to the setting described above.

Furthermore, the method for setting the driving frequency is not limitedto the method for setting the driving frequency lower. For example, whenthe identification information indicates that the video data isgenerated by the moving picture coding method and the moving picturecoding apparatus described in each of embodiments, the voltage to beapplied to the LSI ex500 or the apparatus including the LSI ex500 isprobably set higher. When the identification information indicates thatthe video data conforms to the conventional standard, such as MPEG-2,MPEG-4 AVC, and VC-1, the voltage to be applied to the LSI ex500 or theapparatus including the LSI ex500 is probably set lower. As anotherexample, when the identification information indicates that the videodata is generated by the moving picture coding method and the movingpicture coding apparatus described in each of embodiments, the drivingof the CPU ex502 does not probably have to be suspended. When theidentification information indicates that the video data conforms to theconventional standard, such as MPEG-2, MPEG-4 AVC, and VC-1, the drivingof the CPU ex502 is probably suspended at a given time because the CPUex502 has extra processing capacity. Even when the identificationinformation indicates that the video data is generated by the movingpicture coding method and the moving picture coding apparatus describedin each of embodiments, in the case where the CPU ex502 has extraprocessing capacity, the driving of the CPU ex502 is probably suspendedat a given time. In such a case, the suspending time is probably setshorter than that in the case where when the identification informationindicates that the video data conforms to the conventional standard,such as MPEG-2, MPEG-4 AVC, and VC-1.

Accordingly, the power conservation effect can be improved by switchingbetween the driving frequencies in accordance with the standard to whichthe video data conforms. Furthermore, when the LSI ex500 or theapparatus including the LSI ex500 is driven using a battery, the batterylife can be extended with the power conservation effect.

[Embodiment 7]

There are cases where a plurality of video data that conforms todifferent standards, is provided to the devices and systems, such as atelevision and a cellular phone. In order to enable decoding theplurality of video data that conforms to the different standards, thesignal processing unit ex507 of the LSI ex500 needs to conform to thedifferent standards. However, the problems of increase in the scale ofthe circuit of the LSI ex500 and increase in the cost arise with theindividual use of the signal processing units ex507 that conform to therespective standards.

In order to solve the problem, what is conceived is a configuration inwhich the decoding processing unit for implementing the moving picturedecoding method described in each of embodiments and the decodingprocessing unit that conforms to the conventional standard, such asMPEG-2, MPEG-4 AVC, and VC-1 are partly shared. Ex900 in FIG. 41A showsan example of the configuration. For example, the moving picturedecoding method described in each of embodiments and the moving picturedecoding method that conforms to MPEG-4 AVC have, partly in common, thedetails of processing, such as entropy coding, inverse quantization,deblocking filtering, and motion compensated prediction. The details ofprocessing to be shared probably include use of a decoding processingunit ex902 that conforms to MPEG-4 AVC. In contrast, a dedicateddecoding processing unit ex901 is probably used for other processingunique to an aspect of the present invention. Since the aspect of thepresent invention is characterized by deblocking filtering inparticular, for example, the dedicated decoding processing unit ex901 isused for deblocking filtering. Otherwise, the decoding processing unitis probably shared for one of the inverse quantization, entropydecoding, and motion compensation, or all of the processing. Thedecoding processing unit for implementing the moving picture decodingmethod described in each of embodiments may be shared for the processingto be shared, and a dedicated decoding processing unit may be used forprocessing unique to that of MPEG-4 AVC.

Furthermore, ex1000 in FIG. 41B shows another example in that processingis partly shared. This example uses a configuration including adedicated decoding processing unit ex1001 that supports the processingunique to an aspect of the present invention, a dedicated decodingprocessing unit ex1002 that supports the processing unique to anotherconventional standard, and a decoding processing unit ex1003 thatsupports processing to be shared between the moving picture decodingmethod according to the aspect of the present invention and theconventional moving picture decoding method. Here, the dedicateddecoding processing units ex1001 and ex1002 are not necessarilyspecialized for the processing according to the aspect of the presentinvention and the processing of the conventional standard, respectively,and may be the ones capable of implementing general processing.Furthermore, the configuration of the present embodiment can beimplemented by the LSI ex500.

As such, reducing the scale of the circuit of an LSI and reducing thecost are possible by sharing the decoding processing unit for theprocessing to be shared between the moving picture decoding methodaccording to the aspect of the present invention and the moving picturedecoding method in conformity with the conventional standard.

Each of the structural elements in each of the above-describedembodiments may be configured in the form of an exclusive hardwareproduct, or may be realized by executing a software program suitable forthe structural element. Each of the structural elements may be realizedby means of a program executing unit, such as a CPU and a processor,reading and executing the software program recorded on a recordingmedium such as a hard disk or a semiconductor memory. Here, the softwareprogram for realizing the image decoding apparatus according to each ofthe embodiments is a program described below.

The herein disclosed subject matter is to be considered descriptive andillustrative only, and the appended Claims are of a scope intended tocover and encompass not only the particular embodiment(s) disclosed, butalso equivalent structures, methods, and/or uses.

INDUSTRIAL APPLICABILITY

One or more exemplary embodiments disclosed herein are applicable tofiltering methods, moving picture coding apparatuses, and moving picturedecoding apparatuses. For example, the one or more exemplary embodimentsdisclosed herein are applicable to high-definition image displayapparatuses and image capturing apparatuses such as televisionreceivers, digital video recorders, car navigation systems, mobilephones, digital cameras, and digital video cameras.

The invention claimed is:
 1. A coding and decoding apparatus,comprising: a coding apparatus which codes a first image to generate acoded bitstream; and a decoding apparatus which decodes a second imageon a block-by-block basis, wherein the coding apparatus includes: atleast one first processor; and first storage coupled to the at least onefirst processor, wherein the at least one first processor is configuredto perform first operations for decoding the first image, the firstoperations including: determining a second quantization parameter for afirst Intra Pulse Code Modulation (IPCM) block using a firstquantization parameter used for quantizing a first non-Intra Pulse CodeModulation (non-IPCM) block, the first IPCM block and the first non-IPCMblock being adjacent to each other in the first image; determining afirst filter strength of first deblocking filtering using an average ofthe first quantization parameter and the second quantization parameter;and performing the first deblocking filtering on a boundary between thefirst IPCM block and the first non-IPCM block using the determined firstfilter strength of the first deblocking filtering, wherein the secondquantization parameter is determined using first difference informationindicating a difference between a quantization parameter for a blockwhich is located immediately before a first current block to beprocessed in processing order and a quantization parameter for the firstcurrent block, the first difference information indicating a zero value,wherein the decoding apparatus includes: at least one second processor;and second storage coupled to the at least one second processor, whereinthe at least one second processor is configured to perform secondoperations for decoding the second image, the second operationsincluding: determining a fourth quantization parameter for a secondIntra Pulse Code Modulation (IPCM) block using a third quantizationparameter used for quantizing a second non-Intra Pulse Code Modulation(non-IPCM) block, the second IPCM block and the second non-IPCM blockbeing adjacent to each other in the second image; determining a secondfilter strength of second deblocking filtering using an average of thethird quantization parameter and the fourth quantization parameter; andperforming the second deblocking filtering on a boundary between thesecond IPCM block and the second non-IPCM block using the determinedsecond filter strength of the second deblocking filtering, and whereinthe fourth quantization parameter is determined using second differenceinformation indicating a difference between a quantization parameter fora block which is located immediately before a second current block to beprocessed in processing order and a quantization parameter for thesecond current block, the second difference information indicating azero value.